Early child control

Lingua 121 (2011) 920–941

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Early child control Idan Landau a,1, Rosalind Thornton b,* a b

Department of Foreign Literatures & Linguistics, Ben Gurion University, P.O. Box 653, Beer Sheva, 84105, Israel Linguistics Department, Macquarie University, North Ryde, NSW 2109, Australia

A R T I C L E I N F O

A B S T R A C T

Article history: Received 12 March 2010 Received in revised form 6 December 2010 Accepted 6 December 2010 Available online 15 January 2011

English-speaking children’s emerging knowledge of control is investigated by focusing on the complementation of the verb want, a verb that permits both obligatory control and raising to object (RtO) complements. Children show an intriguing developmental pattern in their use of the infinitival marker to. Initially children produce complements with and without to; our diary data show that among those complements without to are ones in which the null subject is not controlled by the matrix subject. These non-control utterances disappear as children’s use of to increases over time. At the time when to reaches ceiling in control complements, it is entirely absent from raising to object complements. The developmental data are analyzed using Landau’s (2000, 2004, 2006) Agree-based theory of control. On Landau’s account, different kinds of clausal complements (e.g. indicative, infinitive[1_TD$IF], etc.) result from different assignments of tense and agreement on the C and I heads. The acquisition stages are argued to reflect the child’s progressive grammatical hypotheses about the feature composition of possible complements for want. For both control and RtO complements, children initially assign features that result in subjunctive complements. Children’s ‘non-adult’ utterances are all viewed as legitimate complement types made available by Universal Grammar. ß 2010 Elsevier B.V. All rights reserved.

Keywords: Language acquisition Control Non-obligatory control Raising to object Infinitival clauses Subjunctive clauses

1. Introduction This paper investigates the emergence of control in 2-year-old English-speaking children’s productions. The study focuses on the verb want, given that this is the only control verb used with any frequency at this young age. The verb want makes an interesting object of study, however, because in addition to taking obligatory control complements (1a), it is a raising to object (henceforth RtO) verb (1b). Such RtO structures are marked, cross-linguistically. The verb want also takes DP complements and small clause complements (1c, d), although these will not be discussed in any detail.

(1)

a.

I want to push the truck

(control)

b.

I want daddy/him to push the truck

(RtO)

c.

I want the truck

(DP complement)

d.

I want the truck clean

(small clause)

* Corresponding author. Tel.: +61 2 9850 6710; fax: +61 2 9850 9199. E-mail addresses: [email protected] (I. Landau), [email protected] (R. Thornton). 1 Tel.: +972 8 6472324; fax: +972 8 6472907. 0024-3841/$ – see front matter ß 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.lingua.2010.12.005

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In control complements, the missing subject of the lower clause is understood as the subject of the higher clause. In RtO complements, like (1b), this is not the case; the infinitival complement has a different subject, i.e., the NP daddy. Although it is the logical subject of the embedded clause, in English, this NP takes accusative case, as demonstrated by the accusative pronoun him in (1b). Such structures were called ‘exceptional case marking’ (ECM) structures because accusative case was assigned ‘exceptionally’ across the clause boundary to the embedded subject.2 We will use the term ‘raising to object’ instead (Postal, 1974). We use this term to reflect the growing current consensus that the accusative NP moves to the matrix clause to become an object in these constructions, and this analysis is adopted here. Surveying the complements in (1), it is clear that children are faced with a considerable task to sort out the properties of these different clause types, and, in English, this must be accomplished with little help from verbal morphology. Furthermore, the RtO structure is genuinely marked across languages. Given this, it would not be surprising if children did not converge immediately on the correct set of complements. Several studies have now documented the development of one or both of control and raising to object structures in children’s production ([2_TD$IF]e.g. Goro, 2004; Kirjavainen et al., 2009; Norris, 2004) and to these reports we add some new observations from a detailed diary study of one child, Laura. The developmental path that emerges across the children in these studies can be divided into three stages. Once children enter the multiword stage, they soon start to produce the verb want with control complements, both with and without to. Our diary data reveal a further type of utterance that has not been observed previously, except anecdotally (cf. Pinker, 1984:217, n.4). In this early period, there are some utterances that on the surface appear to be control structures that are missing to. On closer inspection of the contexts, however, these utterances turn out to be cases in which the matrix subject does not control the embedded empty subject; it is disjoint in reference. We analyze such examples as instances of ‘non-obligatory control’. An example is given in (2). In this example, the child’s intended meaning is that she wants her mother to push her. In this case, the meaning that would arise if control were intended is that Laura wanted to push herself in the stroller, which is, of course, an impossibility, adding credence to the proposal that this is an instance of non-obligatory control.

(2)

Context: Laura wanted mother to push her in the stroller Laura: I want _ push Laura (1;7.19)

Such ‘non obligatory control’ complements are short-lived, and have disappeared by the second stage. At the second stage, control complements still appear with and without to, but the use of to rapidly increases. At this point, the first ‘precursors’ to adult RtO structures appear. These RtO ‘precursors’ all lack to. Finally, by the third stage, to is obligatory in control complements, and RtO complements start to appear with to. Explaining children’s grammatical hypotheses as they progress through these three stages and converge on the adult grammar is the goal of this paper. It is important to acknowledge that there is considerable discussion of children’s knowledge of control in previous acquisition literature. For the most part, this debate has focused around older 3[3_TD$IF]–6-year-old children’s comprehension of control structures with a variety of lexical verbs in complement clauses and various types of adjunct clauses. Our focus is on the emergence of control structures in 2- and 3-year-old children’s productions, where we seek to explain the presence and absence of the infinitival marker to across development. We review here only those key theoretical claims from the comprehension literature that are potentially relevant for the present study.3 Comprehension data from a number of experiments with pre-school 3[4_TD$IF]–5-year-old children, and experiments based on grammaticality judgment data from McDaniel et al. (1990) have generally demonstrated that children do not steadfastly show adult knowledge of the relationship between the controller and the ‘controllee’ in different types of clauses. To take an example, McDaniel et al. observed that in an object control sentence like (3), younger children did not always require Grover to be the one to jump over the fence, allowing either a sentence internal or external referent. As will become clear, this comprehension finding from older children is incompatible with Laura’s early non-obligatory control productions like (2), which never contain the infinitival marker to.

(3)

Cookie Monster tells Grover PRO to jump over the fence

As Wexler (1992) points out, there are basically 3 types of accounts that relate children’s developing grammar to the adult grammar when working within the framework of Universal Grammar. These accounts, given in (4a–c), could all be invoked to explain children’s developing knowledge of control. To these competence-based accounts, we could also add that 2 The verb want is sometimes argued not to be a true believe-type RtO verb because it fails to passivize. Other desiderative verbs such as mean and intend, that also license for-complements, do passivize, however, so we will simply assume that this is a quirk of want. Furthermore, the verb want passes most of the other RtO tests that believe does (Postal, 1974:176–187). 3 For a review of [13_TD$IF]3–6-year old children’s comprehension of control structures, see Guasti (2002), and Kirby et al. (2010). For discussion of the acquisition of control in languages other than English see Goodluck et al. (2001).

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performance issues, such as the language production process, may have an impact on children’s linguistic knowledge (cf. (4d)). (4)

a.

Constancy: UG principles and constructs are equally available at every stage for the child

b.

UG-Constrained maturation (Growth Theory): UG constrains every stage of child language development, but certain constructs may not be available at certain ages

c.

(Unconstrained) Maturation: Principles of UG may change over time

d.

Performance limitations: Access to UG may be masked by processing limitations or by the language production process

The explanation given by McDaniel et al. (1990) for their experimental findings is a ‘Constancy’ (or ‘Continuity’) account. They propose that children have the relevant constructs from UG, but that children have misanlayzed the structure of (3) as a coordinate structure. The misanalysis means that the noun phrase that would be the controller for adults does not c-command the controllee, with the result that the context is consulted instead to find an appropriate referent for PRO. Wexler (1992) proposes a different account of the experimental data from children that draws on ‘UG-Constrained Maturation’. Wexler claims that, until linguistic maturation takes place at around 4 years of age, children lack the empty category PRO. Pending linguistic maturation, children are forced to give an alternative analysis to any complements containing to, by treating to as a nominalizing morpheme. This means that an utterance like I want to sing is interpreted as I want (the) singing. Given that there is no embedded subject, the agent of the singing is open to interpretation, and this is said to explain children’s failure to enforce control in sentences like (3). In RtO cases, like I want Daddy to sing, maturation of PRO is not an issue, since there is a subject present in the embedded clause. So, according to Wexler, either children have the adult analysis of RtO structures from the start, or, if they stick with the analysis of to as a nominalizing morpheme, then they could treat the embedded phrase to sing as a nominalized phrase with the subject Daddy. Wexler acknowledges that he has focused on children’s interpretations of control utterances and ignored early production data such as that from Bloom et al. (1984) that seem to suggest children know control properties, at least with verbs like want, but he also points to data reported in Pinker (1984:388 fn 5) that suggest potential errors (Wexler, 1992:288 fn.13). Pinker cites Braine (no reference is given) as reporting that a child David produced the utterances want fix it and want come on, in which the intended agent of the embedded verb was not David himself. Such data are taken by Wexler to be compatible with his proposal that PRO is lacking until age 4. Clearly, there is no subject in the embedded clause, but neither do these utterances contain the nominalizing morpheme to which is the purported source of the non-obligatory control reading, so it is not clear that Wexler’s proposal explains these utterances. Crucially, Wexler’s proposal fails to note that the non-obligatory control interpretations arise in children’s productions only when to is absent from the structure. In contrast to the comprehension data, younger children’s production data show a progression through a number of grammatical hypotheses regarding the clausal complements for want well before age 4. In Laura’s grammar, examples like want fix it which we analyze as instances of non-obligatory control, have disappeared by 2 years of age. Thus, the proposal that PRO matures at age 4 does not appear to be adequate to explain the presence and absence of to in control and RtO structures in some children’s early production data. Our account of children’s early knowledge of control does not appeal to linguistic maturation, but offers what Wexler (1992) terms a ‘Constancy’ account, or what we term a ‘Continuity’ account (Pinker, 1984; Crain and Pietroski, 2002). All of UG is assumed to be available to children throughout development, and moreover, in the absence of abundant and decisive positive evidence at the early stages, in order to satisfy their communicative needs, children may temporarily implement UG-compatible options that are not part of the target language. To develop the continuity perspective, we draw on Landau’s theory of ‘the calculus of control’ (Landau, 2000, 2004, 2006), since this theory accounts for the wide variety of forms control complements can take across languages. On Landau’s theory, different types of clausal complement (indicatives, infinitives, subjunctives[5_TD$IF], etc.) result from different assignments of the tense and agreement features within the clausal complement. For any verb, children’s task is to settle on the correct assignment of features for the different complements it selects. For the verb want, for example, children have to figure out that it takes an infinitive clause, and an RtO clause, but not an indicative or subjunctive clause. Should a child assign features that are not correct for the adult grammar, a different type of complement could result. In fact, we propose that at the early stages of production, children produce subjunctive complements for want in contexts of control. This is not surprising since in many languages (e.g., Greek, Arabic, Persian, etc.) control is instantiated with subjunctive clauses. In English, on the other hand, while there are verbs that take a subjunctive complement, subjunctives reflect a formal register that is little used in colloquial speech, and not used to express obligatory control. It therefore seems unlikely that children attempt to use subjunctive complements based on positive input, but rather because they are using feature assignments made available by UG as they attempt to settle on the appropriate types of clausal complement for English. The paper proceeds as follows. Section 2 introduces the early production data from previous literature, and Laura’s data is added in section 3 to lay out the three developmental stages in the acquisition of control. In section 4, we introduce Landau’s theory of control that forms the basis of our analysis of children’s acquisition stages. Section 5 gives an analysis of the child data and section 6 gives a summary and concludes.

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2. Children’s production of control complements There are now several studies that have investigated children’s developing use of control complements, and a consensus over the developmental data in need of explanation has emerged.[6_TD$IF] 2.1. Previous literature Early studies observed that children frequently leave out to in infinitival clauses (cf., Bloom et al., 1984; Bromberg and Wexler, 1995; Harris and Wexler, 1996; Limber, 1978; Radford, 1990; Wexler, 1992). More recent research has shown that, at least with the verb want, children appear to use infinitival to more or less optionally in control complements like I want to go from the time that embedded complements first appear (Goro, 2004; Kirjavainen et al., 2009; Norris, 2004). It has also been observed that when children start to use an embedded subject in utterances like I want Daddy to go, the infinitival to is not optional, but missing altogether (Goro, 2004). In general, researchers have focused on one or other of these puzzles, but not both. In this paper, we also add some new production data to the data set discussed, with the goal of explaining the developmental progression in both the acquisition of control and RtO structures. The earliest study is by Bloom et al. (1984) who study the development of various kinds of infinitival complements in four children from age 2 to 3 years.4 They report that in V-to-V contexts, children start to use the infinitival marker to at varying rates in obligatory contexts from about 25 months. Among the structures of the form V-NP-to-V included in the study are RtO constructions, but also included are tough-constructions (e.g., It’s hard for you to eat your thing) and wh-infinitives (e.g., I’ll show you how to work it). This range of structures with syntactically different properties makes these data difficult to interpret. At any rate, Bloom et al. report that the structures with an intervening NP were acquired later, and only after the children were using to in the V-to-V structures more than 75% of the time. To explain children’s increase in the use of to over time, Bloom et al. appeal to a number of factors that must come together; (i) children’s knowledge of the distribution of the infinitival marker, which has to be learned from the input (ii) prior knowledge of the lexical item to as a preposition and (iii) increased processing capacities. A recent study by Kirjavainen et al. (2009) studies children’s development of infinitival complements using data from 13 children, 12 of them from the Manchester corpus available on CHILDES (MacWhinney, 2000). The data from the 13th child, Brian, was culled from dense data collected for 5 h[7_TD$IF] per week between 2;7 and 3;2. In the data collection period, 861 instances of infinitival complements were collected, incorporating 17 main verbs. Even with dense data collection, few control verbs appear with any frequency. The most frequent verb was want (474 instances), followed by need (244 instances), and go (95 instances) with these 3 verbs providing 813 of the 861 instances. The control verb want was produced with 68 omissions of infinitival to (68/474 = 14%), and the control verb need had 27 omissions (27/244 = 11%).5 Brian’s productions of infinitival complements with and without to are reported to appear at about the same time. To explain the coexistence of infinitival complements with and without to in the first few months in which want and need appear, Kirjavainen et al. appeal to competition between 2 structures in the child-directed input, the want-to schema and the abstract want-X schema. The idea of this usage-based proposal is that if the input supports the want-X schema by a predominance of want-NP constructions, for example, then this schema will be favored, and some omissions of infinitival to will follow. Unfortunately, RtO examples are excluded from the study, so the developmental proposal is limited to control complements. Furthermore, it is not clear how RtO structures, which would have a want-X-to schema could be integrated into the present account. Presumably this schema would compete with the others, but if this is the case, why isn’t to optional in early RtO utterances? A different kind of proposal is mounted by Radford (1990), who proposes that children’s omissions of to are the product of an immature grammar. Radford proposes that children lack the ability to generate functional categories before about 24 months. Lacking the category IP, children generate VP complements instead, giving control and RtO utterances the structures in (5a) and (5b) until the relevant functional categories mature and children can project adult-like structures (Radford, 1990:141). (5)

a.

Want [VP see handbag]

b.

Jem want [VP Mummy [V take] it out]

As will be seen, however, control and RtO structures do not necessarily omit to at the same time. In Laura’s data at stage 2, to is largely present in control complements, while completely absent from the first attempts at RtO complements, rendering Radford’s account untenable. Goro (2004) provides a thorough investigation of the distribution of to-infinitives in child English, using data from Adam 2;3–3;2 (Brown), Sarah 2;3–3;2 (Brown) and Abe 2;4–3;2 (Kuczaj), available on the CHILDES database (MacWhinney, 2000). The first finding is that these children do not overgenerate to; they do not use it erroneously in causative complements (make/let), complements of verbs of perception (see/watch/hear), contracted verb forms (wanna/gonna) or in combination with modals. The forms in (6) are unattested, except for the occasional error. 4

The children studied are Eric, Gia, Kathryn and Peter, whose data is available on the CHILDES database (MacWhinney, 2000). The data included from Brian include want + to, and want plus a schwa (taken to be a contraction of to); data with the contracted form wanna are not included in the counts. 5

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924 Table 1 Adam’s development of infinitival complements. Adam

Control

Omissions of to

RtO

Omissions of to

2;3–2;6 2;6–2;10 2;11–3;2 3;3–3;6

24 59 154 71

2 47 32 1

0 7 192 35

0 6 (85.7%) 190 (99.0%) 3 (8.8%)

(8.3%) (79.7%) (20.4%) (1.4%)

Table 2 Abe’s development of infinitival complements. Abe

Control

Omissions of to

RtO

Omissions of to

2;3–2;6 2;6–2;10 2;11–3;2 3;3–3;6

6 52 114 103

0 5 (9.6%) 2 (1.8%) 0

1 22 14 15

1 (100%) 17 (77.3%) 1 (7.1%) 0

(6)

a.

#John made Mary to go

b.

#I saw John to cross the street

c.

#I wanna to go

d.

#You can to finish the task

Children do undergenerate infinitival to, however, in the complements of want, need and like.6 The children all omitted to to varying degrees in structures in which the complement has an empty subject, that is, in control structures (e.g. I need to go).7 When the omission rate is calculated across the period of about a year that was studied, Adam omits to 34.2% of the time, Sarah omits to 93.9% of the time, and Abe omits it only 4.1% of the time. For structures with an overt subject, that is RtO structures (e.g. I need you to go), the children’s rate of to-omission was higher, with Adam omitting to in 98.5% of his utterances, Sarah 100% (though there was little data for her) and Abe 51.4%. Further investigation of Adam and Abe’s development shows that both children omit to to a greater extent in the later data with RtO complements, with rapid decline in the to omissions in control structures at age 3. The interesting fact to be explained is that children have started to use to in control structures fairly consistently at a time when it is still absent in RtO structures. Goro’s tables for Adam and Abe are replicated above.8 The tables exclude numbers of examples with the contracted form wanna (Tables 1 and 2). Goro reserves the question of the optionality of to in control complements for future research and focuses on providing an explanation of the high omissions of to in the RtO complements. Goro’s proposal assumes an ‘Exceptional Case Marking’ (ECM) structure instead of a raising to object account of the overt subject. Under the ECM account, the matrix verb assigns accusative case to the overt subject (pronoun) across the embedded clause boundary in an example like I want him to go. Goro’s proposal is that languages may vary parametrically in whether they allow Exceptional Case Marking (ECM) into (just) small clauses, as in French, or into infinitival clauses as well, as in English. The idea is that English-speaking children begin with the subset option, and initially produce only small clause complements. Thus, an utterance such as I need you do it would initially have the structure in (7), with the IP layer missing. (7)

I need [SC you do it]

Since children do not overgenerate to, Goro takes this as evidence that they know that the infinitival marker to is an instantiation of [-tense] Infl. Thus, taking note of to in adult ECM utterances like I need you to do it should cause children to generate an IP layer (with the feature [–tense]), thus adopting the English setting of the parameter.9 This account is appealing, but it fails to complete the developmental progression by integrating the data on control. In a larger scale study, Norris (2004) combined all of the data from the 222 American English-speaking children in the CHILDES database to examine the use of infinitival to. Her goal was to relate the optionality of to in control structures to omissions of complementizers in other embedded complements, but here, we ignore complementizer omissions. As already observed in the data from the British English children reported by Kirjavainen et al. (2009), the only verb used with embedded clauses with any frequency is want, and this is Norris’s focus for infinitival complements. Overall, Norris’s aggregate data show that children stop dropping to in control complements with want by age 3 and a half (with a few 6

Goro searched for RtO complements with believe, and he also searched for raising complements, but found none in the transcripts. By complements with an ‘empty subject’, Goro (2004) appears to refer just to control, giving the example John wanted [ e to go]. By complements with ‘overt subject’ complements, Goro apparently intends ECM/RtO, giving the example John wanted [Mary to go] (his (9)). To keep terminology consistent, the terms ‘control’ and ‘ECM’ or ‘RtO’ are adopted here. There is no suggestion that empty subject complements could include non obligatory control (NOC). 8 The tables are adapted from Tables 7 and 8 respectively in Goro (2004). 9 In fact, French, like English, allows verbal small clauses only under causative and perception verbs, and not under vouloir/désirer (‘want’) (see Kayne, 1981). Thus, it is not clear, on Goro’s (2004) proposal, how the French setting can lead English children to produce utterances like ‘‘I want you do it’’. 7

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925

Table 3 Norris’s data on omission of to in Want control clauses (N = 222). Age

Want + PRO clause

Omissions of to

Omission percentage

1;3–2;0 2;0–2;4 2;4–2;8 2;8–3;0 3;0–3;4 3;4–3;8 3;8–4;0 4;0–4;6 4;6–5;0 5;0–6;0

186 708 1308 885 583 228 166 147 124 54

68 191 193 130 26 3 3 0 1 1

37% 27.0% 14.8% 14.7% 4.5% 1.3% 1.8% 0% 0.8% 2%

exceptions, and one child, Nathaniel, who persists). For RtO complements, Norris claims children continue to omit to into the 4-year-old range. In sum, the asymmetry between use of to in control complements and use of to in RtO complements noted by Goro is confirmed in the data studied by Norris (2004), although she notes that it is most robust in Adam’s data, seen previously in the tables from Goro (2004). Norris’s control data for the 222 children are shown in Table 3. There is no suggestion that Norris examined the contexts of these utterances. Since close attention must be paid to the contexts to ‘discover’ utterances with non-obligatory control, they could well be collapsed with the obligatory control utterances in the ‘Want +PRO clause’ column in Table 3. Norris’s proposal for the omissions of to is based on the proposal about the nature of Optional Infinitive structures in Schütze and Wexler (1996) and Wexler (1998).10 On Wexler’s (1998) optional infinitive account, a number of innate constraints, some particular to the linguistic growth of the child, are in conflict in the developing child. Children know (i) that there is an interpretive property that requires both AGR and T in the derivation, but (ii) the only way to satisfy a further child-specific constraint, the Unique Checking Constraint (UCC), is to delete AGR or T from the derivation. Children are thus forced to violate one or other constraint. Norris takes this conflict to account for the optionality of to in control structures; children omit to when the T node is absent from the derivation and produce it when T is present.11 Taking up Wexler’s proposal that the empty category PRO is not available until age 4, Norris proposes that in early control structures children use a pro subject until PRO matures. Use of pro instead of PRO predicts that children should allow non-obligatory readings until age 4, when PRO matures. However, Norris assumes that the representations with pro are only used to express obligatory control – a theoretical anomaly which is not attested in adult grammars. Nevertheless, Norris did not report that the contexts of children’s productions were examined, so it may well be that some non-obligatory control utterances were included in her data. Thus on Norris’s account, control and RtO clauses have essentially the same analysis until maturation takes place; the difference is just that in one case the embedded subject is silent pro, and in the other case it is a pronounced lexical DP. Both are simply ‘immature’ versions of infinitival clauses. To explain the fact that children adopt the use of to in control clauses while they are still omitting it in RtO clauses, Norris suggests that when PRO matures, to is no longer deleted from the derivation because PRO carries a special feature that results in the checking requirements of the Unique Checking Constraint no longer being violated. Thus, there is no need to sometimes omit to in control clauses. In RtO derivations, on the other hand, there is no PRO, and so the omissions of to persist. In short, on Norris’s account to becomes obligatory when PRO matures at around age 4. We see several problems with this account. First, to claim that PRO has a special feature that renders the UCC constraint no longer problematic is stipulatory. Second, this claim is a bit out of step with the data that Norris presents suggesting that to is more or less obligatory by 3;6. Furthermore, it will be seen that in Laura’s data, which is introduced in the next section, omissions of to largely disappear by 2 years of age, so if the obligatoriness of to is a product of linguistic maturation, there is a large disparity in the age at which maturation takes place. 3. Laura’s production data The data reported in this section come from a diary study of one child, Laura. The diary data that are analyzed in this paper start at 1;6 and extend to age 2;6.12 During this period, the corpus of utterances totaled over 4500 utterances. The diary data replicate the developmental facts already established in previous literature, except that Laura’s grammar became adult-like more rapidly. The data from Laura also add some new facts to the overall developmental picture of control structures. As previously observed by Goro (2004), Kirjavainen et al. (2009) and Norris (2004) for other children, Laura also initially omits to frequently in control complements with want, gradually increasing its proportion of use over time. In contrast to her 10 Optional Infinitive structures in English are taken to be ones in which tense or agreement is missing. A typical instantiation would be use of a bare verb in an utterance like Daddy go. 11 The technical details of Norris’s derivations are omitted here. 12 Diary data are jottings in a notebook, often by a parent, of a child’s utterances. Sometimes, it is argued that diary data are not valid because they are not an objective measure of the child’s linguistic competence. The diary observations for Laura were supplemented by video recordings that provide comparison data from her spontaneous speech. The diary data were mined for this paper about 10 years after the diary data were originally collected.

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Table 4 Number of utterances produced by Laura in contexts of control.

1;6–1;7 1;8–1;9 1;10–1;11 2;0–2;1 2;2–2;5

want + VP

want + to + VP

wanna + VP

5 8 16 4 1

2 10 22 23 49

2 6 42 13 3

(56%) (33%) (20%) (10%) (2%)

(22%) (42%) (28%) (58%) (92%)

(22%) (25%) (52%) (32%) (6%)

early uses of control complements, Laura omits to all of the time in her early RtO structures. The fact that Laura’s diary data show the same developmental pattern as seen in audio-taped naturalistic data is taken to validate its use. The diary data also introduce a type of utterance that has hitherto been reported only anecdotally. Diary observations have the advantage that they allow us to ‘catch’ some utterances that are relatively short-lived, and might go unobserved in transcript data, which tend to be based on fortnightly audio or video recordings. The diary notes capture utterances such as I want push Laura in which Laura intended someone else to push her. Although the number of these early utterances is limited, it is significant that they appear within a limited timeframe and then disappear. Drawing on Landau’s (2000, 2004, 2006) account of control, these early utterances will be analyzed as instances of non-obligatory control. Further, anticipating our analysis of children’s utterances that lack to as subjunctive clauses, the data presented in this section explore the consequences of a subjunctive analysis by examining Laura’s use of agreement and case in matrix and embedded clauses. 3.1. Early productions Laura was an early talker; two word combinations appeared at 1;5 months, and three and four word combinations were plentiful at 1;6 years. Productions with embedded complements appeared as early as 1;6 months. In the very first attempt at control in the diary notes, Laura used her own name, as shown in (8), but it was the only example of this kind. (8)

I want Laura swing (1;6.27)

In contexts of ‘control’, when Laura wanted to do some action herself, Laura produced adult-like complements with the infinitival marker to, as in (9a), utterances with the contracted form wanna, (9b), and examples in which the infinitival marker to is absent, as shown in (9c). (9)

a.

Context:

Father is reading morning paper

Laura:

I want to see paper (1;8.10)

b.

Mother:

Mother offers to get Laura’s umbrella

c.

Laura:

I wanna get it (1;9.23)

Context:

Mother started to zip up Laura’s jacket

Laura:

I want do that (1;10.11)

The three variations appeared more or less at the same time, as can be seen in Table 4. The table shows the number of productions with want, want to and wanna at five time intervals from 1;6 to 2;5 years. Given that the status of wanna as a separate lexical item or a contracted form of want + to is open to debate, we have followed the lead of previous researchers and excluded the examples with wanna from the discussion.13 When Laura started to produce embedded complements, more than 50% were missing the infinitival to. For quite a few months there was some fluctuation in the structure used to express obligatory control, just as Goro (2004) had observed. Fig. 1 illustrates the proportion of use of to in control structures from 1;6 to 2;5. The omissions of to in control structures were mostly gone by just after 2 years of age, about a year and a half earlier than Norris (2004) had observed for the aggregate CHILDES data. It is interesting to note that once infinitival to became productive in control structures, at around 2;0, want + to appeared with VP ellipsis. Presumably, once to was obligatory in the I head, it had assumed the features required for licensing of ellipsis. This development is illustrated in Fig. 2. Let us now turn to situations in which Laura wanted something to happen, or wanted someone else to do something for her, situations typically expressed with RtO structures. The data show that Laura took some time to acquire this structure, as did the children studied by Goro (2004) and Norris (2004). In the earliest recordings in the diary, there were 5 utterances in which Laura intended for someone who was present to do something, but did not specify the intended agent with a lexical DP or pronoun. As mentioned similar examples have 13 A reviewer notes that Laura’s use of wanna appears to plunge after she starts to use to, asking if this is important. At this stage we do not know why this is, and whether or not this trend also appears in other children’s data. Future studies using experimental methodology may provide an answer.

[()TD$FIG]

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Fig. 1. Laura’s control structures.

[()TD$FIG]

Fig. 2. Laura’s increasing use of VPE with to, and control with to.

appeared in anecdotal reports such as Pinker (1984).14 Without the context notes in the diary entry, these utterances look like attempts at control, but as noted earlier, a control analysis is impossible for some examples. For example, in (10d), it is unlikely that Laura is asking to change her own diaper, and the context notes do not indicate this. Although there are only 5 examples, they are very clear. These will be taken to represent a stage in development that has not been explained previously. A dash is used to represent the missing agent in the examples. (10)

a.

Context:

Laura wanted mother to push her in the stroller

Laura:

I want _ push Laura (1;7.19)

b.

Context:

Laura wanted mother to dance

Laura:

I want _ dance (1;8.05)

c.

Context:

Laura wanted mother to open the door to the study

Laura:

I want door open. I want _ open door. (1;9.09)

d.

Context:

Laura wanted father, not her mother, to change her diaper.

Laura:

I want _ change it (1;9.26)

e.

Context:

Laura wanted mother to brush her (=mother’s) teeth

Laura:

I want _ brush your teeth, mommy (1;10.25)

14 Further searches of Adam’s data (Brown, in CHILDES) reveal that Adam also produced similar examples. For example, at 2;6.17 (file 8), he says ‘‘no want stand head’’, which clearly means ‘I don’t want her to stand on her head’. And at 2;10.16 (file 16) Adam says ‘‘do want feed you?’’ in a context where it means ‘Do you want me to feed you?’. Adam’s examples continued until quite late, but this is expected, since he dropped to until about 3 years of age. Similarly, a search of Nicole’s data (in the Manchester corpus, CHILDES) reveals a similar example. At 2;1, Nicole says ‘‘I want do’’ four times, but her intended meaning is ‘I want mummy do. . .’. We can assume that further NOC examples will be observed in other children’s data once close attention is paid to contexts in which utterances with want are produced.

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Table 5 Laura’s successive hypotheses about the form of RtO structures.

1;6–1;7 1;8–1;9 1;10–1;11 2;0–2;1 2;2–2;5

Want + VP (no subject and omission of to)

Want + NP + VP (omission of to)

Adult RtO structure

1 3 1 0 0

1 1 3 44 28

0 0 2 2 13

(50%) (75%) (25%) (0%) (0%)

(50%) (25%) (75%) (96%) (68%)

(0%) (0%) (4%) (4%) (32%)

[()TD$FIG]

Fig. 3. Laura’s hypotheses for RtO structures from 1;6 to 2;5.

Around this time Laura started to use want with embedded clauses that contained an overt subject, either a lexical DP or a pronoun. The first such example emerged at 1;11;28, and just 3 such examples appeared before age 2;0. This structure rapidly gained favor, and there were 44 examples of this structure between 2;0 and 2;2. This is the structure that Goro (2004) argued has an embedded predicate that is a small clause. (11)

a.

I want you do it (2;1.09)

b.

I want Daddy sing (2;1.10)

c.

I want you buy some at the store for me (2;1.16)

d.

I want you carry me get the mail (2;1.21)

e.

Mummy, I said I want you come here (2;2.22)

Productions like the ones in (11) were always missing to, unlike Laura’s earlier productions in control contexts, where use of the infinitival to marker fluctuated, gradually increasing over time. Given that some of Laura’s productions contained 3 clauses, it seems unlikely that processing limitations were responsible for the absence of to, making a non-linguistic explanation of the data unlikely. The numbers of productions for the various structures produced by Laura in contexts in which adults would produce RtO structures are summarized in Table 5, and graphed in Fig. 3. The asymmetry seen across children between the use of to in control complements and in (what become) RtO structures can be seen in the graph of Laura’s data in Fig. 4. The line that is labeled ‘Subjunctive/RtO’ in the legend shows the progression from what we will take to be subjunctives (e.g. I want you go) to adult-like RtO utterances. At around 2;5, Laura figured out the adult structure for RtO. Some representative examples are given in (12). (12)

e.

I just want somebody to play with me (2;5.02)

f.

I don’t want you to put your toe in my yogurt (2;5.16)

3.2. Morphology in Laura’s productions In Landau’s (2000, 2004, 2006) theory, different kinds of clausal complements differ in the features for tense and agreement specified on the heads I and C in the syntactic representation (see section 4[9_TD$IF]). Although English speakers might intuitively conceive of control infinitives and subjunctives as very different kinds of clauses, in Landau’s syntactic theory, they are minimally different. We will argue that this minimal difference means that, should children err in their initial assignment of features, they could end up producing a subjunctive clause instead of an infinitival clause, as is correct for

[()TD$FIG]

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Fig. 4. Asymmetry in Laura’s use of to in obligatory control and in development of RtO structures.

English. We will develop the proposal that in the early stages, English-speaking children hypothesize that want takes a subjunctive complement, instead of an infinitival one. In this section, the properties of English subjunctive complements are outlined, and the relevant predictions explored in Laura’s data set. In English, desiderative and directive verbs may take a complement in the subjunctive mood, but in modern English, want does not. Another feature of subjunctive clauses is that the embedded verb bears no morphology (cf. (20)). Since use of morphology can only be tested with 3rd person subjects in English, we need to look at embedded clauses with a 3rd person subject. In early child English, 3rd person subjects are notoriously few and far between, because much early discourse is between ‘you and me’. However, among the 77 examples of the form want + NP + VP recorded in Laura’s productions in the diary notes, there are 8 examples with an embedded 3rd person subject. Of these, 7 of the 8 examples lack agreement. Some examples are given in (13), and the example that goes against the prediction is given in (13e). (13)

a.

I don’t want Boomer [the dog] lick my face (2;2.13)

b.

I don’t want my supper be cooked (2;2.18)

c.

I want daddy sing (2;1.11)

d.

I want daddy come in (2;1.19)

e.

I want my baby goes right here! (2;2.3)

The absence of morphology on the embedded verb in Laura’s want complements can be compared with the presence of morphology in embedded indicative clauses under the verbs think and hope. At age 2;1, there are 7 cases recorded in the diary notes, with morphology present on the embedded verb, and 1 example that is missing agreement, but this was an example with don’t rather than doesn’t, see (14f).15 There are 9 further examples of utterances with embedded clauses under know, think, pretend, tell and say at 2;2, all of which express morphology on the embedded verb. (14)

a.

I think I spilled my milk (1;11.30)

b.

I think you’re sick (2;1.6)

c.

I hope it’s not poopie [dirt on her shoes] (2;1.11)

d.

You know it’s not your bedtime (2;1.17)

e.

These shoes fit! I think it feels comfortable! (2;1.27)

f.

I hope it don’t spill [plane as it lands] (2;1.10)

The diary data also show a contrast in the morphology expressed on the embedded verb and the matrix verb. Again, only utterances with a 3rd person subject are informative. In every one of the recorded examples culled from the diary corpus between 1;6 and 2;6, the verb want shows 3rd person agreement.16 15 In general, the form doesn’t appears only once 3rd person morphology is stable on main verbs, and frequently follows a period in which don’t is the form used (Thornton and Tesan, 2007). 16 Children of this age are often said to be in the ‘optional infinitive’ stage in which verbal morphology on main verbs and auxiliary verbs is frequently missing (e.g. Wexler, 1998), so Laura’s data look different from some of the data reported in the literature. There are big individual differences in the extent to which children omit morphology, however (cf. Phillips, 2010). For example, at age 2, Eve uses optional infinitives 80% of the time, and Adam at 2;5 about 70% (see Fig. 1), but Phillips observes that there is considerable variation in the use of morphology from one session to the next. Laura’s use of optional infinitives is lower than that reported for some other children. Analysis of 43[14_TD$IF] mi[15_TD$IF]n of videotape at 1;11 shows that Laura was using 3rd person present morphology 84% of the time overall (i.e. 37/44 times in the intelligible utterances, with repetitions excluded). With main verbs, Laura was using 3rd person morphology 73% of the time (i.e. 8/11 cases).

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(15)

a.

Kanga wants medicine (1;10.14)

b.

Daddy wants my fruit chew, mummy (1;11.10)

c.

May wants a dog (1;11.19)

d.

Daddy wants ketchup (1;11.21)

e.

Daddy wants his taco (2;0.6)

f.

Mummy wants his . . . she’s jacket (2;1.23)

g.

He wants to eat his bone by hisself (2;3.22)

Subjunctive clauses have another distinguishing characteristic – the embedded subject is in the nominative case, in contrast to RtO clauses which take accusative case. Again, this is not easy to test in child English, because we need to restrict our attention to 3rd person pronominal subjects. Of the 8 want examples with a 3rd person embedded subject, 3 have pronominal subjects. In 2 cases, Laura uses the nominative pronoun he, but in one case him surfaces, although Laura immediately self-corrected to an adult like RtO example, suggesting it was a speech error.17 The fact that it was the latest appearing example also suggests Laura was poised to converge on the adult grammar. The examples are given below. (16)

a.

I want he go away (repeated 3 times) (2;2.14)

b.

I want he play Dalmatians (2;3.22)

The two occurrences above, which occur before 2;4, bear nominative case and there is no infinitival to marker; the six later examples bear accusative case. In all but the first example when accusative case appears, it does so in combination with the infinitival marker to. (17)

a.

I don’t want him go yet (2;4.23)

b.

I want him to go to work (2;4.04)

c.

I don’t want her to get in the shower (2;4.09)

d.

I want him to stay here with us (2;4.23)

e.

I don’t want him to be dead (2;4.28)

f.

They want us to be at the house (2;5.02)

We end this section by using the data from Laura combined with that from previous literature to summarize children’s developmental progression as they acquire productive use of control and RtO complements. (18)

Stage 1:

Control complements with or without to

Stage 2:

Control complements show increasing use of to

Non-obligatory control complements without to Non-obligatory control complements are gone RtO complements appear only without to Stage 3:

Control complements always incorporate to RtO with to starts to appear

In the next section we present the basic features of Landau’s (2000, 2004, 2006) theory of control, which we will use to explain the stages of acquisition. 4. Landau’s theory of control Control is one of the earliest topics studied in generative grammar (starting with Rosenbaum, 1967), and accordingly, has been analyzed from widely varying theoretical perspectives. In the present section we lay out the fundamental aspects of the theory we will adopt in analyzing the data, referring the reader to Landau (2004, 2006) for a more detailed account.

17 There has been some discussion of the case of embedded subjects in earlier literature. In a discussion of the development of RtO structures, Pinker (1984) entertained the idea that utterances like I want you do it contain a finite embedded clause, and investigated this in Adam’s data. Pinker reported that Adam’s data was not revealing. Reportedly, Adam used accusative marking 102 times as compared with 3 instances of nominative marking. But since all but one of the instances with accusative marking occurred in d’you want me VP, or want me VP environments, Pinker suggests these constructions may have been unanalyzed question markers. From our perspective, the 3 instances of embedded pronouns with nominative case show that Adam is also likely to have gone through a stage in which he hypothesized embedded subjunctive clauses. Pinker also reports anecdotal data from Wasow’s child, who reportedly said I don’t want she + VP several times, providing further data supporting our analysis.

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There have been a number of analyses of control in the last 30 years (see, among others, Bresnan, 1982; Dowty, 1985; Hornstein, 1999; Jackendoff and Culicover, 2003; Manzini, 1983; Sag and Pollard, 1991; Williams, 1980), but they were primarily concerned with English.18 We draw on Landau’s (2000, 2004, 2006) theory because it paints a typological landscape of control based on a broad set of crosslinguistic evidence. The analysis of early child English falls naturally out of this theory. The key question is this: What determines the distribution of PRO? This is simply the question of what distinguishes clausal complements whose subject is null and necessarily controlled by a matrix argument, from those whose subject is possibly lexical and distinct from any antecedent. In other words, this is the basic distinction between obligatory control and non-obligatory control. As Landau shows, the distinction cuts across the types of clausal complements (infinitives, inflected infinitives, subjunctives and indicatives). Below we focus on the analysis of the infinitival and subjunctive complements which are relevant to the child data. 4.1. Crosslinguistic data In English, control (‘obligatory control’, or OC) is represented by infinitival complements. Certain predicates select infinitival RtO and/or indicative complements as well. But, because English lacks subject pro-drop, the option of nonobligatory control (NOC) into complements is unattested. Example (19) shows the types of complement selected by the verb expect; it permits obligatory control as in (19a), RtO as in (19b) and indicative complements with no control, as in (19c). The fact that non-obligatory control is ruled out is shown in (19d). (19)

a.

Johni expects [PROi to leave early].

OC

b.

John expects Louisei [ti to leave early].

RtO

c.

John expects [that Louise will leave early].

No control

d.

* Johni expects [that proi/j will leave early].

NOC

English also permits subjunctive complements, at least in formal registers. These complements, selected by desiderative and directive verbs, feature a bare verbal stem. (20)

a.

Her Royalty ordered the master of ceremonies that no speech be allowed before her own.

b.

George demanded that he visit the construction site first.

Notice that in (20b), George and he can corefer, implying that the English subjunctive, unlike its Romance and Slavic counterparts, is not obviative. (Compare this with corresponding example that contains the complementizer for: *Georgei demanded for himi to visit the construction site first, in which the pronoun has to take disjoint reference from George). This difference will play a crucial role in the analysis to be presented in section 5. Turning to the Balkan languages, we find that in Greek, Bulgarian, Romanian[10_TD$IF], etc., infinitives are either entirely absent or used only in frozen forms. Subjunctive complements are used to express both OC and NOC complements (indicative complements show no control), the choice being determined by the matrix verb (see Landau, 2004 and the references therein). We refer to OC complements in these languages as C(ontrolled)-subjunctives and NOC complements as F(ree)subjunctives.19 Note that like English, Balkan subjunctives are non-obviative. (21)

a.

I

Mariai prospathise PROi/*j na

the Mary tried.3sg

PRO

diavasi.

PRT read.3sg

‘Mary tried to read.’ (Greek: C-subjunctive) b.

Ioni vrea ca

Dan/proi/j să rezolve

problema.

Ion wants that Dan/pro PRT solve.3sg the-problem ‘Ioni wants Dan/himi/j to solve the problem.’ (Romanian: F-subjunctive) Verbs selecting C-subjunctives are (translated as) try, help, know how, dare, manage, begin, etc. Verbs selecting F-subjunctives are believe, want, hope, prefer, persuade, ask, forbid, etc. The contrast is keyed to tense. The matrix and the embedded event in F-subjunctives are temporally distinct, whereas in C-subjunctives only one event takes place.20 As a result, tense sequencing is allowed in the former, but not in the latter (Varlokosta, 1993). Thus, F-subjunctives, which display NOC are considered to be ‘tensed’, and C-subjunctives, which express OC, are ‘untensed’ in this system. 18

Borer (1989) is a notable exception. The subjunctive mood in these languages is realized by a preverbal particle (the verbal morphology is the same as in the indicative) and in Romanian and Albanian, by a designated complementizer, often omitted. 20 Notice that this is a semantic notion of tense, and is not related to the morphology used to express tense. 19

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(22)

a.

tora, o

Yanis elpizi/theli

na

figi

avrio.

now, the John hopes/wants PRT leave.3sg tomorrow ‘Now, John hopes/wants to leave tomorrow.’ (Greek: F-subjunctive) b.

*tora, o

Yanis kseri /arxizi

na kolimbai avrio.

now, the John knows-how/begins PRT swim.3sg tomorrow ‘Now, John knows how/begins to swim tomorrow.’ (Greek: C-subjunctive) Interestingly, Landau (2000) has shown that the same tense distinction divides OC verbs in English into two types, those allowing partial control and those forcing exhaustive control. As shown below, the distinction has to do with whether, in a suitable context, PRO can or cannot properly include the controller (partial control is marked with a ‘+’ subscript). Thus, want (and prefer, hope, plan, etc.) allows partial control, while manage (and dare, begin, refrain, etc.) forces exhaustive control. (23)

a.

Yesterday, John wanted to finish the work tomorrow.

b.

*Yesterday, John managed to finish the work tomorrow.

c.

(We thought that) the chairi wanted [PROi+ to gather at 6].

d.

*(We thought that) the chair managedi [PROi+ to gather at 6].

For English, the generalization is that complements like (23a) that allow tense sequencing (that is are ‘tensed’) license partial control (23c), whereas complements like (23b) in which this is not possible, do not (23d). For the Balkan languages, the generalization is that tensed complements display NOC (F-subjunctives), whereas untensed complements display OC (C-subjunctives). We have seen that in both English and the Balkan languages, complements can be tensed or untensed, but this does not account for whether the complement expresses OC or NOC. There is an additional factor to consider; this is agreement. While the Balkan subjunctive verb carries agreement, the English infinitival verb does not. This suggests that the grammar (or calculus) of control is sensitive to the interaction of two features: semantic tense, [T], and morphological agreement, [Agr]. In fact, [T] and [Agr] seem to play symmetrical roles. Keeping tense constant, we see that agreement yields NOC (21b) and lack of agreement yields OC (23a) (also allowing partial control) – in tensed complements. In untensed complements, agreement has no effect: whether it is present (21a) or absent (23b), OC obtains (and partial control is disallowed). Keeping agreement constant, we see that tense yields NOC (21b) and no tense yields OC (21a) – in Agr-bearing complements. In Agrless complements, tense has no effect: whether it is present (23a) or absent (23b), OC obtains. As Landau (2004, 2006) shows, the same pattern recurs in other types of complements observed across languages.21 4.2. How the system works The crosslinguistic picture calls for a theory that distinguishes various types of complement clauses: raising infinitives, control infinitives (inflected or not), subjunctives (tensed or not) and indicatives. The theory also needs to distinguish two types of nominal phrases that can appear as the subject in these clauses: DP/pro vs. PRO. Finally, some ‘‘interface rule’’ is required, to link up the different clause types with the DP (subject) types. For clause typing, Landau adopts the standard [T] and [Agr] features. These features may show up on both the I(nfl) and C(omp) heads of the complement. Since selection is local, a matrix V can only determine the [T] value of the embedded I via the intermediate head C. Thus C also bears a [T] feature, although an uninterpretable one, since semantic tense is interpreted on I, as usual. Standard feature checking between I and C (‘‘deleting’’ [T] on C) guarantees the desired tense dependency.

(24)

The syntax of selected tense V ..... [CP C [±T] [IP I[±T] VP]]

[T] is interpretable on I [T] is uninterpretable on C

selection

checking

Consider the tense distinctions we need. Selected tense is expressed by a [T] feature on C. Unselected tense (i.e., unrestricted by the matrix predicate) simply involves no [T] on C. Hence, infinitive and subjunctive complements, whose tense depends

21 Inflected infinitives bear agreement (hence their name). When they are also tensed, NOC obtains (European Portuguese), but when they are untensed, OC does (Hungarian). Languages with a rich complementation system, like Welsh, Basque and Turkish, provide strikingly systematic evidence for this pattern. Verbs selecting tensed complements contrast in their OC-NOC profile according to whether or not they license agreement in the complement; while verbs selecting inflected complements contrast in their OC-NOC profile according to whether or not they license (semantic) tense in the complement (see San-Martin, 2004; Słodowicz, 2007; Tallerman, 1998).

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Table 6 Feature specifications for obligatory control. Obligatory control

I C

Exhaustive control infinitive

Partial control infinitive

Balkan C-subjunctive

[
T,
Agr] [
T]

[+T,
Agr] [+T,(+Agr)]

[
T,+Agr] [
T]

Table 7 Feature specifications for non-obligatory (or no) control. No control

I C

Balkan F-subjunctive

English subjunctive

Indicative

Raising to object

[+T,+Agr] [+T,+Agr]

[+T] [+T,+Agr]

[+T,+Agr] 1

[+T] (no C)

on the matrix predicate, bear [T] on their C head. Dependent tense subsumes two cases: The embedded tense is distinct from the matrix tense or identical (anaphoric) to it. Distinct dependent tense, in turn, may be realized either as irrealis (desiderative, propositional) or realis (factive); Landau encodes both as [+T] on I. Anaphoric tense is expressed as [
T] on I (small clauses may lack [T] altogether). As noted, the presence and value of [T] on C is determined by the lexical properties of the selecting predicate. Verbs like want and prefer select irrealis complements – [+T] in this system. Verbs like manage and dare select anaphoric tense – [
T] in this system. Finally, verbs like believe and announce do not impose any [T] value on their complement. Consider next the specification of [Agr]. Uncontroversially, [+Agr] on I encodes overt morphological agreement. Landau follows the traditional analysis of infinitival I as being specified [
Agr] (so-called ‘‘abstract’’ agreement). This captures the distinction between indicative and infinitival clauses. How is the distinction between control I and raising I to be expressed? Contra Martin (2001), there is no solid basis to the claim that raising and control infinitives differ in their tense properties (see Baltin and Barrett, 2002; Hornstein, 2003); in fact, raising infinitives are tensed, hence the difference must lie in [Agr]. Following Borer’s (1989) notion of ‘degenerate Infl’, Landau assumes that I in raising infinitives (selected by seem, believe, etc.) is radically unspecified for [Agr].22 (25)

Specifying [Agr] on I a.

overt agreement ) [+Agr]

b.

abstract agreement ) [
Agr]

c.

no agreement ) 1

This brings us to specification of [Agr] features on C, which is the only place where properties of the positive input do not translate seamlessly into a UG-given feature assignment. The reason is that agreement is rarely manifested on complementizers. A null C, in principle, could be either [+Agr] or not (Landau speculates that [
Agr] is unattested, reducing potential variablity). By assumption, the [Agr] slot on C is parasitic on [+T]. Thus, C with [+T] (dependent tense) may be either [+Agr] or unspecified for [Agr], while [
T] (anaphoric tense) or lack of [T] (independent tense) on C entail unspecified [Agr]. This is summarized below. (26)

Specifying [Agr] on embedded C a.

[+Agr] ) [+T]

b.

otherwise ) 1

Of present interest are complements with irrealis (i.e., dependent) tense. These may be headed either by a fully specified C[+T,+Agr] or by a partially specified C[+T] (ignoring RtO complements for now). Landau speculates that the two choices correspond to non-obviative and obviative clauses, respectively. Thus, the first type includes English subjunctives and Balkan F-subjunctives; the second type includes Romance subjunctives and English for-infinitives. Tables 6 and 7 summarize the feature specifications of some (not all) of the clause types describable by the system. A comparison of control structures across languages brings out one striking generalization. Whenever the embedded clause contains both agreement and semantic tense – there is no control. Obligatory control is witnessed only when either [T] 22

This may be a side-effect of the absence of a CP layer and, possibly, the reason why these infinitives lack an EPP position (Chomsky, 2001).

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or [Agr] is negatively specified. Thus, of the two sets of syntactic environments – those that require a lexical subject (or pro) and those that require PRO – it is the former that constitutes a natural class. PRO is the elsewhere case of lexical subjects.23 We now need to define the ‘interface rule’ between the clausal features and the subject features. For the latter, we use the independently needed referential distinction between PRO and lexical DPs, here encoded by an interpretable feature [R]. (27)

Specifying [R] on DPs a.

Lexical DP, pro ) [+R]

b.

PRO ) [
R]

Roughly, referential DPs are [+R], ‘anaphoric’ DPs are [
R]. [
R] is an interpretable feature that requires an antecedent for identification. The link to the clausal features can now be stated in terms of an uninterpretable counterpart of [R], present on functional heads like I and C (cf. the analogous dual manifestation of f-features). The split between [+T,+Agr] and the elsewhere cases is mediated by an uninterpretable [R] feature as follows. (28)

R-assignment Rule For X[αT,βAgr] 2 {I, C. . .}: a.

1 —> [+R]/X[__], if α=β=‘+’

b.

1 —> [
R]/elsewhere

Put simply, whenever I or C are specified for [+T,+Agr], they automatically come to bear [+R]; any other feature constitution – [+T,
Agr], [
T,+Agr] or [
T,
Agr] – is associated with [
R]. Lack of [T] or [Agr] renders the rule inapplicable – no [R] value is assigned. Licensing of the subject simply means checking off whatever uninterpretable feature(s) I and C bear. Since lexical DPs are specified with an interpretable [+R], they will be able (in fact, required) to check off the uninterpretable [+R] found on I/C specified for [+T,+Agr]. Since PRO bears interpretable [
R], it will be obligatory if either I or C is negatively specified for [Agr]/[T] (while still specified for the other feature). In the remainder of this section, we illustrate the derivation of three types of complements: tensed control infinitive, English subjunctive, and RtO, since these are the three structures we will argue are instantiated in children’s early grammars. The purpose of this illustration is to show how the correct assignment of [T]/[Agr] values to the complement I and C heads automatically yields the control type (OC or NOC). This will allow us to appreciate, in the next section, what effects on control would result from the child’s misvaluation of these features. A typical derivation of a tensed control infinitive is illustrated with the verb want, the focus of our investigation in child grammars.

(29)

OC-infinitive (tensed) a. John wanted [PRO to say a few words]. b.

[CP DP .. F .. [CP C[+T,+Agr,+R] [IP PRO[–R] [I’ I[+T,–Agr,–R] [VP tPRO ..]]]]] Agree [+Agr,+R] Agree [+Agr,+R]

Agree[+T, ±Agr]

Agree [–Agr,–R]

The [R] values of C and I are fixed by (28). Of interest in this derivation is the mediation of control by C. [+R] on C is checked against the matrix F (= I) while [
R] on I is checked by PRO.24 Note also that Agree (C,I) matches the f-features of I and C; the opposite values of [Agr] on these heads do not conflict, since they only reflect morphological spellout. A lexical DP or pro, instead of PRO, would crash this derivation: The [
R] feature on I would remain unchecked. The learning implication is that a child who correctly analyzes the infinitival to as [+T,
Agr] would not generate it in conjunction with a lexical subject or pro. We return to this prediction in the next section. Consider next the derivation of an English subjunctive, where control does not apply.

(30)

English subjunctive (no control) a.

John prefers that no promises be made to the newcomers.

b.

[CP ... DP ... F ... [CP C [+T,+Agr,+R] [IP [I’ I[+T] [VP DP/pro[+R] ...]]]]] Agree [+Agr,+R]

Agree [+T]

Agree [+Agr,+R]

23 This is somewhat simplified, as Landau shows that OC can also result in F-subjunctives, if the features of I and C ‘cancel out’ by mutual checking. This option has no bearing on the current discussion so we put it aside. 24 This route through C is what allows the partial control effect; see Landau (2000, 2004) for details.

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The subjunctive C in English is non-obviative, which means it is specified [+T,+Agr] and, by virtue of the R-assignment rule, also [+R]. The latter feature is checked off by a lexical DP subject or pro. Note that the subject also checks (abstract) agreement against C, not I. Although not presently crucial, it is an interesting question what is the source of nominative case in the subjunctive clause, given the lack of agreement. If it is C, then case is checked together with [Agr] as part of Agree (C,DP/pro) in (30b). If nominative case is associated with I (hence, with semantic tense), an additional Agree relation is formed between I and the subject, to check off that feature. Two points are important concerning the subjunctive. First, a PRO subject would crash the derivation: The [+R] feature on C would remain unchecked. Second, the embedded subject is assigned nominative case (and not accusative), a result secured whether we associate that case with [T] or [Agr]. The learning implications are: (i) a null subject in these contexts can only be analyzed as pro, not PRO (yielding NOC, not OC); and (ii) an overt pronoun in these contexts would be marked nominative. These predictions are addressed in the next section. Finally, we sketch the derivation of an RtO construction.

(31)

Raising-to-Object (no control) a.

John wanted her to say a few words.

b.

[CP [IP DPj I [vP tj [ V+v [ DP i [ t V [IP ti [I’ I[+T] [VP ti ...]]]]]]]]] Agree [+Agr,+R]

Agree [ACC]

We step aside of various technical debates surrounding the analysis of RtO (see Runner, 2006). For simplicity, we assume that the embedded subject raises to the matrix Spec,VP position, whose EPP feature is induced by light v (Chomsky, 2007), although more complex alternatives are possible (Koizumi, 1993). In this execution, the familiar ‘exceptionality’ of RtO complements consists in their reduced size – bare IPs, without a CP layer. As suggested above, this may be the source of their [Agr]-defectiveness: The I head is specified for [+T] only. The absence of a CP layer is crucial in allowing the matrix light v to probe the embedded subject (thereby assigning it accusative case): An intervening CP projection would have blocked this Agree relation by the Phase Impenetrability Condition (Chomsky, 2000). The learning implication is that RtO clauses in the input would not be analyzable by the child as long as they are taken to be CPs, a point we take up in our proposal for children’s development. 5. Early child control The diary data presented from Laura and the production data from the children studied by Goro (2004), Kirjavainen et al. (2009) and Norris (2004) combine to demonstrate the 3 stages of development summarized in (32). While the proposal we develop for children’s development rests entirely on data from the verb want due to the fact that this is the only verb used with any frequency in 2-year-old children, we suggest our proposal may apply more broadly to the ‘control’ grammar of English. (32)

Stage 1:

Control complements with or without to

Stage 2:

Control complements show increasing use of to

Non-obligatory control complements without to Non-obligatory control complements have disappeared RtO complements appear only without to Stage 3:

Control complements always incorporate to RtO with to starts to appear

In his paper on the typology of control, Landau (2004) addresses the learnability of clause types and their properties, asking what aspects are universal, and what aspects are open to parametric variation. Landau proposes that the lexical semantics of the matrix predicate provide the critical data for children to break into the system. As Landau puts it ‘‘part of knowing what manage means is knowing that it takes a complement with no tense operator (i.e., anaphoric tense); part of knowing what prefer means is knowing that it takes a complement with dependent tense; and part of knowing what believe means is knowing that it takes a complement with independent tense’’ (Landau, 2004:870). In other words, UG makes available the tense properties of the complement for a particular verb. Following this logic, knowing what the verb want means, children should select a complement with dependent tense. This is accomplished by assigning a [+T] value to C, which is matched with the local I head in the complement. For this reason, children do not attempt to use the indicative option for the complement of want (given that indicative tense is independent). In contrast to tense values, the agreement values of a complement vary across languages. Positive evidence provides children with the information that decides the agreement value of the clausal complement. The child must ascertain whether the verb in the clausal complement morphologically spells out [+Agr] features or not. This observation of the ambient language translates, again through UG procedures, to a feature assignment for [Agr] on the I head. If the verb

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936 Table 8 Laura’s acquisition path. Structure

DPi DPi DPi DPi DPi

want want want want want

Stage 1 (1;6–1;9), control with or without to, NOC without to ecj VP eci VP eci to VP DPj VP DPj to VP

U U U

Stage 2 (1;10–2;1), NOC disappears, to-less RtO appears U U U

Stage 3 (2;2–2;5), to-less control disappears, to in RtO appears

U U U

expresses overt agreement, the I head is given a [+Agr] assignment. An infinitival marker such as to in English will represent abstract agreement in the form of [
Agr], and RtO infinitives lack any specification for [Agr]. The specification of [Agr] on C is less transparent, as discussed in section 4.2. The suggestion was that [+Agr] on C is parasitic on [+T]. Note that in this system ‘tensed’ complementizers could be either [+T] or [+T,+Agr]. In finite clauses, this dichotomy corresponds to the distinction between obviative and non-obviative subjunctives, respectively. The learning cue for the child is indirect: Obviative complementizers, it seems, are always lexical. Thus a lexical complementizer in the input is potentially [+T] (obviative) or [+T,+Agr] (non-obviative), but a null one can only be non-obviative. This system is indeed underdetermined by the input, but as Landau observes, obviation is often an idiosyncratic property that must be mastered case by case. The challenge children face is to figure out how the various clausal complements in their language match up with the various feature assignments. Given that the feature assignments for tense fall out of knowledge of lexical semantics of the matrix predicate, we can assume that it is the agreement values that could potentially be assigned in error by children. We will propose a syntactic analysis of the types of utterances identified at the 3 stages in Laura’s grammar based on Landau’s theory, and suggest that it extends to children more generally, although the age at which children transit through the different stages is assumed to vary. The grammatical constructions observed at the 3 stages are summarized in Table 8. 5.1. Stage 1 (1;6–1;9) Clausal complements for the verb want are among the earliest verbal complements for English-speaking children. In Laura’s grammar, clausal complements with want appeared at 1;6. Given that the verb want was used meaningfully and productively, it can be assumed that Laura knew the lexical semantics of want and assigned it a complement with dependent tense that is realized by a C specified as [+T]. The verb want does not appear with a complementizer in the input (which could imply obviation), so in the absence of this information, the C head is assigned the features [+T,+Agr]. The [+T] value of C must be matched by a [+T] value on the local I (to be checked off), hence the infinitival I is assigned [+T] as well. The final feature assignment to be decided on is the [Agr] value of the I head. This is where children could mistakenly choose an option that is used to express control in other languages but is not correct for English. For an adult, the presence of the infinitival marker to in the input would lead to a [
Agr] assignment to the I head. However, it seems reasonable to suppose that in the absence of sufficient experience, young children of age 18 months to 2 years may not have yet fully analyzed the presence of to in the input. Let us suppose that, given that there is no morphological inflection on the verb in the infinitive clause, children do not attempt to assign the I head a feature; they initially they assign the I head no [Agr] feature at all. What is the typological profile that results from assigning [Agr] no value, rather than [
Agr] as in the adult grammar? The resulting complement is neither an indicative nor an infinitive clause – it is a subjunctive one, with the feature assignment of formal English subjunctives, as seen previously in (30): C is [+T,+Agr] and I is [+T].25 In addition to subjunctive complements, adult-like clausal complements with to also appeared in Laura’s productions almost immediately. Laura apparently soon internalized the presence of to in infinitival complements and gave the I head (that is, to) a [
Agr] feature assignment: C is [+T,+Agr] and I is [+T,
Agr]. At Stage 1, then, both of the complement types, the English subjunctive and the adult infinitive, coexisted in Laura’s grammar, and the literature shows this is the same for other children.26 At some point, the subjunctive structure must be purged from the grammar, however, an issue to which we return. First, let us consider the properties of the clauses without to that we are analyzing as subjunctive clauses. First, we can note that the child uses the bare form of the verb as the subjunctive form. This is because child has hypothesized that there is no [Agr] feature on I. Therefore, the expectation is that the child would not spell out any 25 The reviewers ask why children initially produce English-like subjunctive clauses and not clause types of other languages, especially typologically related ones such as German. The reason is that children use the verbal agreement features in the input to guide their hypothesis. They do not randomly assign features to [Agr]. Given that the infinitival verb embedded under want doesn’t exhibit any verbal agreement, they choose to assign no [Agr] feature to the I head. There is no positive input to suggest that children should assign the embedded I head a [+Agr] feature. Nonetheless, had they assigned a [+Agr] feature to the I head, the resulting [+T,+Agr] would have produced a Balkan-type F-subjunctive, which is also manifested as a NOC complement. Nor is there any reason for children surrounded by English to produce inflected complements to want (as found in German), for this would imply an inconsistent expression of [+Agr] – both lack of inflection (in the[16_TD$IF] input) and presence of inflection (in the output). 26 It is not clear whether the subjunctive analysis precedes the adult one, or whether the 2 options are simply implemented alongside each other. This could also vary from child to child. Here, for the sake of proposing a concrete analysis, we assume that the subjunctive analysis is the first hypothesis.

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agreement features on the embedded verb. This verb form with no morphology also has the advantage of contrasting with the indicative form, which we showed Laura inflects (see (14)). Let us now consider the properties of the embedded subject. Recall that in Landau’s theory, the [+T,+Agr] features on C in subjunctives imply [+R] as well. This means that the subject of the embedded clause must be either a lexical DP subject, or pro. Since English is not a pro-drop language, the possibility of pro subjects is excluded for adults, and only lexical subjects are found in formal English subjunctives. However, given that the child utterances under discussion occur at the beginning of the multi-word stage, it is reasonable to claim that pro subjects have not been eliminated as a possible empty category.27 This would predict that at Stage 1, English-speaking children can generate subjunctive complements with a DP subject or an embedded pro subject. Laura’s earliest utterance with a complement for want (in which context notes suggest that she intended obligatory control) was an example with a DP subject I want Laura swing (8).28 Most of her early utterances are of the form I want _ swing, which can be taken to be a subjunctive complement with an embedded pro subject. The structure is shown in (33). In this case, coreference between the matrix subject and the embedded subject is optional, not obligatory since subjunctives in English are not obviative. The [+R] feature on C is properly eliminated by the [+R] feature on the pro subject. (33)

[CP . . . Ii want [CP C[+T,+Agr,+R] [IP proi/j[+R] [I’ I[+T] [VP ti/j swing.]]]]]

The proposal that Laura permits the verb want to take a subjunctive complement with a pro embedded subject now explains the non-adult productions between 1;7 and 1;10 in which the embedded subject differed from the matrix subject (cf. (10)). As mentioned, in a context when Laura wanted her mother to push her in the stroller she said I want _ push Laura (meaning ‘I want you to push Laura’). These utterances are similar to the I want pro swing utterances, only there is no coreference be[1_TD$IF]tween the matrix and embedded subjects – this is non-obligatory control. An important prediction follows from the proposal that children’s early productions feature subjunctive complements. If, as we propose, the embedded subject is pro and not PRO in the utterances like I want _ push Laura, the infinitival marker to should never show up in the embedded clause. In the infinitival complement of want, the embedded I head is specified as [+T,
Agr], and therefore it will also be specified [
R]. This adult setting for infinitive-taking want (see Table 6), crucially forces obligatory control and use of PRO. Turning to the empirical data, in all of the 5 cases like I want _ push Laura where the intended interpretation was non-obligatory control – there was no infinitival to. These findings thus not only demonstrate that Laura used want with subjunctive complements and pro subjects, but also that she did so under strict supervision of her grammar: the feature-assignments of the I and C heads were consistent with those of pro. It is hard to see any other reason for her avoidance of to in these constructions – at the same age where she does use to in control.29 In our view, it is likely that previous research has missed many of these non-obligatory control utterances in the absence of detailed contextual notes. It is also possible that the stage is fleeting for many children – nevertheless, it is a stage of child English that must be accounted for. 5.2. Stage 2 (1;10–2;1) At Stage 2, Laura continued to express control with subjunctive complements as well as with infinitival complements, but the non-obligatory control utterances disappeared. Since NOC utterances have the same surface form as utterances intended as obligatory control, parents’ misunderstandings may cause children to drop the use of pro for disjoint reference and bring about use an overt subject in the embedded clause. Use of the subjunctive structure with an embedded pro subject continues for a while in obligatory control contexts, however. These subjunctive complements used in lieu of an infinitival complement gradually decreased over time, and had completely disappeared from Laura’s productions by 2;2. On the analysis we have presented, children can express coreference between the matrix and the embedded subject in more ways than adults (either with PRO in an infinitival clause or pro in a subjunctive clause), so positive evidence can only confirm children’s hypothesized grammar. This situation clearly presents a learnability problem. We need to explain what causes children to purge the subjunctive alternative from their grammars. In this context, it is worth noting that languages typically avoid having both infinitives and subjunctives. Typically, a language either lacks one of the forms (e.g., Balkan languages lack infinitives) or, if it has both, they are used to express distinct meanings (e.g., in Romance subjunctives are 27 For many years, following Hyams (1986), it was assumed that children acquiring English begin with the setting of the pro-drop parameter that permits null subjects. However, later research showed that the distribution of null subjects in child grammars differed from the distribution in adult pro-drop languages (e.g. Roeper and Rohrbacher, 1994; Valian, 1991; Wang et al., 1992). This led Rizzi (2005) to propose that children’s null subjects in tensed clauses are licensed by a different parameter, the Root Subject Drop parameter. The null subjects of interest to us are in an embedded clause, however, suggesting that they cannot be the product of the Root Subject Drop Parameter, and must be vestiges of a non-adult value for the pro-drop parameter. Since the NOC and OC examples we assume to contain pro disappear by about age 2;2, we can conclude that this parameter assumes its adult English value at around this age for Laura. 28 The pronoun I and Laura enter accidental coreference, since the two forms, one 1st person and one 3rd person cannot be coindexed. If binding were possible, the utterance would violate Principle C. 29 A possible objection to the subjunctive hypothesis might allude to the fact that the complements in Laura’s early productions do not contain complementizers, unlike the adult English subjunctive, where the complementizer is obligatory. The objection is not compelling, though, since our argument is that children’s subjunctive structures are not produced as an attempt to replicate adult input; subjunctives in adult English are highly formal, do not occur with the verb want, and are likely to be extremely infrequent in the input to toddlers.

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obviative, and control is expressed with infinitives). This complementarity in adult languages has been argued to follow from a blocking principle (Farkas, 1992). In the acquisition literature, a learning principle is often posited that ensures that, over time, one of two competing forms is eliminated from a child’s grammar. For example, The Uniqueness Principle, proposed by Wexler and Culicover (1980), instructs the learning mechanism to assign one structure for each meaning. Adopting this principle, it can be assumed that Uniqueness forces the child’s grammar to discard the non-adult subjunctive analysis from the grammar. Once adult infinitive structures with want to were productive, Laura also produced utterances with want and verb phrase ellipsis, as illustrated in Fig. 2. According to Lobeck (1995), verb phrase ellipsis is licensed by a head specified for ‘strong agreement’. In the split IP phrase structure that Lobeck assumes, (morphological) tense is the head expressing ‘strong agreement’ in tensed clauses, and in infinitival clauses, infinitival to is the relevant head. If we take infinitival to to be expressing ‘strong agreement’ (as expressed by the [
Agr] specification on I in Landau’s system), then it is not surprising that VP ellipsis appeared once adult control structures were productive; two rather different constructions emerged – obligatory control and VP ellipsis – both triggered by a non-trivial, abstract aspect of grammatical knowledge. The obligatory control structures incorporating to that became increasingly productive at this age (that is, Laura’s infinitival complements) are assumed to contain PRO; a lexical DP or pro instead of PRO would crash the derivation because the [
R] feature on I (which is specified [+T,
Agr]) would remain unchecked. Thus, a child who correctly analyzes the infinitival to as [+T,
Agr] should not generate a lexical subject or pro subject in the embedded clause. It is not possible to prove that the embedded null subject is PRO and not pro in these complements, but at this stage of development there were no utterances with the surface form I want Daddy to swing, in which a lexical DP embedded subject appears together with the infinitival marker, which one might expect if pro was a possibility. Utterances with this surface form did not appear until considerably later in development, when Laura adopted a RtO analysis, which we take to be a separate development, at Stage 3. The data suggest that at this point, Laura did not generate lexical DP subjects in structures with the analysis in (29b). The only way that Laura was able to express a lexical DP embedded subject was to generate utterances with the form I want Daddy X with a subjunctive complement. Laura’s subjunctive structures with a lexical DP embedded subject such as I want you do it were most productive between age 2;0 and 2;2, when 44 such examples were recorded. There are two important predictions that follow from the proposal that Laura continued to generate subjunctive complements, now with lexical DP subjects. The first prediction is that the embedded verb should carry subjunctive morphology and the second prediction is that the embedded subject will bear nominative case. Both of these predictions are borne out in Laura’s data presented in section 4, although the data are limited. In complements of want with an embedded 3rd person DP/pronominal subject, Laura did not use 3rd person morphology on the verb, as shown in (13). This contrasted with the complements of lexical verbs such as think and hope, in which 3rd person morphology was expressed on embedded verbs with 3rd person subjects (cf. (14)). It also contrasted with the overt morphology on the verb want in matrix sentences with 3rd person subjects (cf. (15)). With respect to nominative case, Laura produced a few utterances with nominative case on the embedded 3rd person subject (e.g. I want he go away), as shown in (16), before she acquired the adult RtO structure. As noted in section 4, similar examples were discussed by Pinker (1984), which we take to support our analysis. 5.3. Stage 3 (2;3–2;5) By Stage 3, the control structures with a subjunctive complement and a pro subject were gone, and Laura had replaced them with adult control structures with an infinitival complement. The subjunctive structures with an embedded lexical DP or overt pronominal subject continued to be produced up until about 2;4, at which time change was initiated. Presumably, Laura had heard a good number of RtO structures in the input, but had not been able to come up with the appropriate grammar to generate them. Why is this, given that the analysis of the infinitival marker to (as [+T,
Agr,
R]) was already in place, and was being utilized in control structures? The problem is that the feature specifications of C and I are unable to generate RtO sentences because the [
R] feature on I cannot be checked by a lexical DP. That is, in a sentence like I want Daddy to do it, the [
R] feature on to cannot be checked by the lexical DP Daddy. Finally, at 2;4, Laura came up with the two changes that provided a solution to this problem. First, she took the radical step of truncating the embedded CP to IP. With an IP complement, the matrix light v could now probe the embedded subject and assign accusative case, as in adult RtO structures. Second, she changed the feature specification of I so that it was appropriate for RtO to – we return to this. Presumably, these two changes could take place in either order or simultaneously. Nothing rests on the ordering. In Laura’s grammar, CP truncation may have occurred prior to feature revaluation of I, given that her very first attempt at adult RtO, in (16a) (I don’t want him go yet) contained a pronoun with accusative case, but not the marker to, which may indicate she had not yet settled on the correct feature assignment for I. Let us consider the change in feature assignment in more detail. Previously, when Laura revised her initial subjunctive hypothesis and adopted the adult analysis of control, she had to adjust the feature specification of the embedded I from the subjunctive [+T] with no [Agr] specification to the infinitival [+T,
Agr]. With the change to [
Agr] came the use of the infinitival marker to (as well as VP ellipsis). Now Laura was moving from subjunctive structures with embedded lexical DP subjects to RtO structures containing to, by truncating CP to IP. This truncation had to be accompanied by a change in the feature specification of I. At this point Laura’s analysis of to for infinitival complements was [+T,
Agr] – but this was incompatible with a lexical subject (given the derived presence of [
R]). This suggests why Laura’s first attempt in (17a) at an

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Table 9 Laura’s acquisition path. Structure

Stage 1 (1;6–1;9)

Subjunctive/NOC DPi want C[+T,+Agr] proj I[+T] VP Subjunctive/control DPi want C[+T,+Agr] proi I[+T] VP Infinitive/control DPi want C[+T,+Agr] PROi to[+T,
Agr] VP Subjunctive DPi want C[+T,+Agr] DPj I[+T] VP RtO DPi want DPj to[+T] VP

U

Stage 2 (1;10–2;1)

Stage 3 (2;2–2;5)

U

U

U

U

U

U

U U

adult RtO structure with accusative case on the pronoun omitted an infinitival marker; the feature specification of this marker was incompatible with RtO. In fact, the I head in the adult RtO structure lacks an [Agr] feature altogether (see Table 7). On these grounds it would be reasonable for children to hypothesize that RtO structures do not have an overt infinitival to marker, but this is contrary to fact. However, with time, adult RtO structures with to provide the positive input to bring about change. The positive input clearly suggests that there is another possible feature assignment for to. Following the truncation of CP, this to can no longer be allowed to bear [
R]. Laura therefore had to impoverish the ‘control to’ by removing its [
Agr] feature, thereby forming the ‘RtO to’ which is just [+T], with no value for [Agr]. In effect, Laura had to ‘‘subjunctivize’’ to so that it became consistent with a lexical DP subject. Note that this dual analysis of to is unavoidable in any theoretical account of the distinction between control and RtO complements in English. The ambiguity is morphologically invisible, and hence difficult for children to internalize, a fact that is confirmed by the late acquisition of RtO structures that is documented in the literature.30 The stages of Laura’s development, and what we hypothesize is indicative of children’s development more generally, are summarized in Table 9. The table gives the syntactic representations for her progressive hypotheses, focusing on the crucial values for tense and agreement on the I head, since this is where the ‘misvaluation’ occurs. 6. Conclusion The acquisition task of the child is to use the resources of Universal Grammar and, in conjunction with the input data, form hypotheses about the properties of the ambient language. In some cases, children cannot wait around for the data, or the input data are not sufficiently rich, and then children must form a hypothesis in the absence of experience. However, the expectation is that the child’s hypothesized grammar will be in accord with the continuity hypothesis and reflect properties of UG, as reflected in other human languages. We have given such an account in the present paper. As Laura attempted to converge on the properties of control and RtO structures, she implemented syntactic representations that were not correct for the adult grammar of English, but were possible ways of expressing control cross-linguistically. The proposal that Laura, and most likely English-speaking children in general, initially produce subjunctive complements rather than infinitival complements is unsurprising on Landau’s theory of control. Within Landau’s Agree-based theory of control (Landau, 2000, 2004, 2006), acquiring the complementation for any lexical verb is seen as a ‘‘journey’’ through a series of hypotheses about the feature composition of its clausal complements. The fundamental idea of Landau (2004) is that the finite-nonfinite distinction is neither binary nor primitive – it is decomposable into various feature combinations, which define a scale of clause types along the finiteness dimension. Mood labels such as ‘‘subjunctive’’ and ‘‘infinitive’’ are mere shorthand for such combinations. In particular, the (non-obviative) subjunctive and the irrealis infinitive (found with want) are barely distinguishable in this system. Should a child initially make the incorrect feature assignment for a given complement, they could end up producing a subjunctive complement, instead of an infinitival one. Both subjunctive and infinitival com[12_TD$IF]plements are headed by C specified [+T,+Agr], which selects an I specified [+T]. The single difference between them, in English, is that the infinitival to is further specified [
Agr] and the subjunctive zero inflection lacks [Agr] altogether. This distinction is not only minimal, but also morphologically invisible. Given the lack of direct evidence bearing on the [
Agr]/no [Agr] choice, it is only natural to expect a certain indeterminacy as to the [Agr] values associated with want complements. The crucial point, however, is that the child’s initial engagement in two options, and the prolonged hedging between them, is not a case of ‘‘grammatical schizophrenia’’. The child is committed to one piece of the puzzle (namely, the [+T] value) while still searching for ways to converge on the other piece (namely, the

30 The arduous acquisition path to the adult RtO structure in English should cause no surprise. This structure is crosslinguistically very marked, occurring in very few languages with very few verbs. Its relative productivity in English is quite exceptional, and possibly requires some deviation from UG. Chomsky states (1981:17): ‘‘It is a ‘‘marked property’’ of English that [RtO structures are] grammatical. Note that in French or German, for example, the corresponding sentences would have the form . . . with PRO, rather than . . . with an overt lexical item. . . It seems, then, that [RtO] reflects some modification or relaxation of conditions of Universal Grammar; we would predict that unless presented with explicit examples such as [RtO sentences], a child learning English would assume that the structures should be as in French or German, with PRO as subject of the embedded infinitival, rather than adopting a marked option’’.

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[Agr] value). On the decompositional account that we endorse, these are principled consequences: both the known piece (i.e., the fact that the child entertains an indicative complement for want only once in the entire data set) and the unknown piece are exactly what we predict and cannot be anything else. Thus, this account offers the right kind of balance between rigidity and lenience that seems to be called for by our developmental data. Previous accounts of children’s development have tended to focus on either children’s acquisition of control complements or RtO complements. Our proposal explains children’s developmental progression for both types of complements for want, and, in principle, it extends to other control verbs as well. There is still much to investigate, however. It will be important to test the developmental progression we have charted using experimental methods such as elicited production. 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