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Sentence production with verbs of alternating transitivity in agrammatic Broca's aphasia
Journal of Neurolinguistics 18 (2005) 57–66 www.elsevier.com/locate/jneuroling
Sentence production with verbs of alternating transitivity in agrammatic Broca’s aphasia Roelien Bastiaanse*, Ron van Zonneveld Department of Linguistics, Graduate School for Behavioral and Cognitive Neurosciences (BCN), University of Groningen, P.O. Box 716, AS 9700 Groningen, The Netherlands Received 23 April 2004; received in revised form 15 November 2004; accepted 15 November 2004
Abstract Bastiaanse, Koekkoek And Van Zonneveld (2003) hypothesized that individuals with Broca’s aphasia have problems with sentences in which the verb and its arguments are not in their base position. The present study is meant to test this hypothesis with the help of verbs with alternating transitivity: transitive: the boy breaks the glass; intransitive or unaccusative: the glass breaks. Superficially seen, the latter sentence is less complex (subject–verb) than the first (subject–verb– object), but from a theoretical point of view, the unaccusative reading (the glass breaks) is more complex, because the theme is in subject position, which is not the base position. A production test was presented to patients with Broca’s aphasia and with anomic/Wernicke’s aphasia, in which transitive and unaccusative sentences with the same verbs were elicited. The results show that broca patients are significantly better in producing the transitive sentences than the unaccusative ones, whereas there is no difference for the patients with anomic/wernicke’s aphasia. Furthermore, an error analysis reveals that the large majority of the errors made by the patients with Broca’s aphasia are transitive sentences while the picture depicts the unaccusative reading. This pattern does not occur in the patients with anomic/Wernicke’s aphasia. The results are taken as support for the hypothesis that sentences in which the verb and its arguments are not in their base position are difficult for patients with broca’s aphasia. q 2005 Elsevier Ltd. All rights reserved. Keywords: Broca’s aphasia; Agrammatism; Verbs; Unaccusatives; Transitivity; Word order
* Corresponding author. Tel.: C31 50 3635558; fax: C31 50 3634900. E-mail address: [email protected] (R. Bastiaanse). 0911-6044/$ - see front matter q 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jneuroling.2004.11.006
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1. Introduction The speech production of agrammatic Broca patients is characterized by so-called telegraphic speech, in which bound and free grammatical morphemes are frequently omitted or substituted. Several experiments have shown that both in comprehension and in production, Broca patients also encounter word order problems. Bastiaanse, Koekkoek, and Van Zonneveld (2003), Bastiaanse, Rispens, Ruigendijk, Juncos Raba´dan, and Thompson (2002) demonstrated that Dutch Broca patients have problems with sentences in which the verb or the object are not in their base position. This, together with the evidence from comprehension and grammaticality judgement experiments, led to the generalized hypothesis that all sentences with derived order are difficult to produce and comprehend in agrammatic Broca’s aphasia. This is called the Derived Order Problem Hypothesis (DOP-H). The general idea is that every language has a basic order, for example Subject–Verb–Object (SVO) for English and Subject–Object–Verb (SOV) for Dutch. All orders different from the basic order are derived and therefore, difficult to produce and comprehend/parse. For example, for Dutch, the DOP-H predicts that matrix clauses, in which the verb is in second position, are difficult. For English, yes/no questions, which are derived, since the auxiliary is before the subject, should be hard to produce. This was confirmed by a study of Bastiaanse and Thompson (2003). The present study focuses on sentences with derived subjects. The DOP-H predicts that these sentences will be hard to produce for Broca patients.1 1.1. Sentences with derived subjects: unaccusatives When ‘normal’ intransitive verbs are produced in sentences, the subject is often the agent, as in (1). These are so-called unergatives. There is another group of intransitive verbs, the so-called unaccusatives in which the subject of the sentence is not the agent, but the theme, as in (2). (1) the boy is speaking (2) the girl is falling It has been argued (see, for example Grimshaw, 1987; Levin and Rappaport-Hovav, 1995) that in sentences with an ergative verb, the subject originates as an object. Sentences such as (2) are thus derived from (3):
1 Note that the DOP-H only takes so-called overt movement into account and that, therefore, it is relatively independent from the often changing theoretical accounts within the Government and Binding (GB) framework. More recent theories also have the concept of covert movement, that is, non-visible movement. Hence, movement or merge operations that do not change the basic order are not supposed to be difficult for Broca patients. For example, in recent theories of GB, the subject is VP-internally generated and moves covertly to SpecIP. These kinds of covert movement are irrelevant to the DOP-H.
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A special group of verbs are those with ‘alternating transitivity’ (Levin, 1993), which can be used with either the agent or the theme in the subject position. When the agent is in subject position, the result is a transitive sentence, as in (4). When the theme is in subject position, this results in an unaccusative sentence, as in (5). Accordingly, verbs of this ‘break’-type must be analyzed as having one argument structure with two possible subcategorisation frames: one frame has an agent-subject and a theme-object, and one frame has a theme-object, that has been moved to subject-position. These structures will be referred to below as ‘the transitive reading’ and ‘the unaccusative reading’, respectively. Note that this analysis is reminiscent of (the second part of) Burzio (1986) generalization, stating that a verb which fails to assign accusative case fails to theta-mark an external argument. Hence the object is forced to move to the position of the external argument, the subject2. (4) the woman breaks the glass
Just like in (3), the theme in (5) is supposed to have been moved from an underlying object position. So, although (5) is superficially seen less complex than (4), in terms of linguistic theory (5) is more complex, because the subject is derived by object-to-subject movement. 1.2. Theories with respect to unaccusativity in relation to agrammatism There are several important theories with respect to the present study to the production of sentences with transitive and unaccusative verbs. The first one is from Kegl (1995) and called the Syntactically Enriched Verb Entry Hypothesis (SEVEH). This hypothesis predicts that any construction that requires movement of a noun phrase from one argument position to another, between d-structure and s-structure, such that the lexically specified arrangement of arguments would be permuted, will result in production problems. Another theory comes from Lee and Thompson (2004) and Thompson (2003) and is called the Argument Structure Complexity Hypothesis (ASCH). It states that verb complexity, either manifest as a high number of arguments associated with the verb, or a lack of direct mapping of verb arguments to sentence slots, renders verb (and thus sentence) production difficulty. This hypothesis predicts that verbs with one argument are more difficult to produce than verbs with two arguments and that (sentences with) unaccusative verbs are more difficult to produce than (sentences with) unergative verbs. This was confirmed in several experiments. The present study compares the production of verbs with alternating transitivity at the sentence level. We tested Dutch agrammatic speakers with Broca’s aphasia. 2 The first part of this generalization states that a verb which lacks an external argument fails to assign accusative case (Burzio, 1986, 178–179).
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In Dutch, the word order of the matrix clause is subject–finite verb–object. In the transitive condition, the agent is supposed to be in subject position and the theme in object position, whereas in the unaccusative condition the theme is supposed to be in the subject position. The SEVEH predicts that the transitive structure will be easier than the unaccusative structure. It is unclear what the ASCH predicts because the transitive version includes more arguments than the unaccusative one, but in the unaccusative sentences there is a lack of direct mapping. The DOP-H predicts, like the SEVEH that production of unaccusative structures is more difficult, because the theme is not in its basic position, as it is taken to be derived by object-to-subject movement.
2. Methods 2.1. Subjects We were primarily interested in the performance of individuals with Broca’s aphasia. In advance, six non-brain-damaged adult speakers were tested, to ensure that the items elicited the intended sentences. It was decided not to test a new control group of non-braindamaged speakers, but to use a control group of fluent aphasic speakers instead, as this might reveal more interesting results with respect to performance patterns. Eight patients with Broca’s aphasia and eight patients with anomic/Wernicke’s aphasia were tested. The aphasia type was established with the Dutch version of the Aachen Aphasia Test (AAT; Graetz, De Bleser, & Willmes, 1992) and confirmed by both the speech therapist and the examiner. The (spontaneous) output of the Broca patients was characterized by telegraphic speech. None of the Broca patients showed articulatory impairments that might have interfered with the test results. The production of both the anomic (nZ5) and the Wernicke’s (nZ3) patients was characterized by severe word finding difficulties and a limited number of paraphasias. The main difference between the patients with anomic and Wernicke’s aphasia was the degree of their comprehension deficit: auditory comprehension (as measured on the AAT) was more impaired in the Wernicke patients than in the anomic patients. All aphasic subjects were right-handed and aphasic due to a single stroke in the left hemisphere at least three months prior to testing. Relevant data are given in Table 1. 2.2. Materials In order to test the subjects’ ability to construct sentences with verbs in the transitive and unaccusative reading, a sentence elicitation task was developed. A picture was Table 1 Age (meanCrange), gender (mZmale, fZfemale) for the Broca’s and the anomic/Wernicke’s patients
Broca Anomic/Wernicke
Age
Gender
50.00 (20–68) 55.00 (31–70)
4 m, 4 f 5 m, 3 f
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Fig. 1. An example of the test. The verb in infinitive form is provided to the patient: luiden ‘to ring’.
presented to the patient with the intended verb (the infinitive) printed underneath. Only verbs with alternating transitivity were used. Pictures were drawn to elicit either a transitive or an unaccusative sentence. An example is given in Fig. 1 and the verbs are given in Appendix 1. Originally, the test contained 30 items, 15 transitive and 15 unaccusative. During the pilot period, however, when the non-brain-damaged speakers were tested, one item (to open) turned out to be difficult in the unaccusative reading (the door opens), so it was removed from the task. Therefore, the final task consisted of 14 verbs, each used twice, once in the transitive and once in the unaccusative condition (total 28 items). The order of the items was pseudo-random: seven items occurred first in the transitive condition, seven items first in the unaccusative condition. 2.3. Procedure and scoring Scoring was done both quantitatively and qualitatively. For the quantitative scoring a correct/incorrect system was used. A sentence was considered to be correct if it contained the required verb and thematic role(s) and if the thematic roles were in the required position. Some verbs allowed object omission in the accusative reading, for example, he is ringing and he is ringing the bell. Sentences with object omissions in this condition were counted as correct3, but omission of obligatory objects-for example, she breaks-was counted as an error. Omission of determiners was ignored. One construction was difficult to score: in Dutch the infinitive is in clause final position. If the (Broca) patients use an ellipsis, for example, klokken luiden ‘bells ringing’ it is unclear whether klokken ‘bells’ is in subject or object position. This happened only three times, in one patient, and it was decided to count these as correct in the unaccusative condition (the obligatory thematic role has been realized), but as incorrect in the transitive condition (the agent role is left out). 3 This happened only two times. Post hoc analysis with these items removed did not change the significance level.
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Since it was hypothesized that the unaccusatives were more difficult, this was also the most conservative way to score. For the qualitative analysis, a scoring system was developed post hoc on the basis of the most frequent errors produced by the Broca patients, since we were primarily interested in their error pattern. The following categories were distinguished: transitive/intransitive (the man cooks the soup/it cooks); intransitive/transitive (the ball rolls/he rolls the ball; the book burns/I burn the book); subject omission (he rings the bells/rings the bells; other (multiple errors, semantic paraphasias, nil reactions etc.).
3. Results 3.1. Quantitative analysis Since the groups of subjects are relatively small, statistical testing was done by using nonparametric tests. In Table 2, the results of the quantitative analysis are given for the two aphasic subgroups. The individual data are given in Appendix 2. For the Broca’s patients, sentence construction in the unaccusative condition is significantly more difficult than in the transitive condition (Wilcoxon, zZK1.995, pZ0.0499). For the anomic/Wernicke’s patients the unaccusatives are slightly easier, but this difference is not significant (Wilcoxon, zZK0.316, pZ0.789). 3.2. Qualitative analysis In Table 3, the results of the qualitative analysis are given (individual data in Appendix B). As can been seen from this table, the difference between the two conditions for the Broca patients is entirely caused by one error type: the production of a transitive sentence when an unaccusative sentence was supposed to be produced. Each of the Broca patients produces two or more of these errors and for seven of the eight Broca patients, it is the most frequent error in the unaccusative condition. Only the Broca patient with the lowest score produces more errors in the category ‘rest’. The data of the fluent patients show that this is not an artefact of the test: they produced transitives instead of unaccusatives as often as the other way around. This group makes many errors that do not concern argument structure, such as semantic paraphasias (for example, target: the glass breaks, realized: the drink will be broken) and paragrammatic sentences (target: the boy is tearing the letter, realized: Pete is going to tear4 on the letter). In sum, for the Broca patients, producing sentences in the unaccusative condition is significantly more difficult than in the transitive condition; when they make an error, the result is most often a sentence with an agent, that is, a transitive sentence. This difference between the two conditions is not found for the fluent patients. 4 In Dutch, this construction is ungrammatical not only because a PP instead of an NP is produced, but also because the future tense cannot be used to describe the picture (*de jongen zal aan de brief gaan scheuren).
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Table 2 Mean number correct (proportions correct) in the transitive and intransitive conditions for both aphasic subgroups
Broca’s aphasia Anomic/Wernicke’s aphasia
Transitive
Unaccusative
9.88 (0.71) 6.38 (0.46)
5.00 (0.36) 7.00 (0.50)
Table 3 Results of the error analysis (tr4unac: transitive instead of unaccusative sentence and the other way around; -subject: subject omission; other: all other errors; trZtransitive, unacZunaccusative) Error type/
tr4unac
Condition/
unac
tr
unac
Subject Tr
unac
Other tr
Broca Anomic/ Wernicke
50 17
6 14
1 0
3 0
21 40
24 47
4. Discussion It is hard for speakers with Broca’s aphasia to produce sentences in which the theme is in subject position, even though these sentences are expected to be less complex when only the surface structure is taken into account. In the unaccusative condition, only a subject and a verb need to be produced, whereas in the transitive condition an object must be realized as well. Notice that in the transitive condition, the object is hardly ever left out. Apparently, producing a simple S–Vfin–O sentence when the verb is given is not extremely difficult for this group of Broca patients. The results are in line with the DOP-H, which predicts that production (and comprehension) of sentences in which the word order is derived is impaired in Broca’s aphasia. According to Grimshaw (1987) and Levin and Rappaport-Hovav (1995), the unaccusative sentences as used in the experiment are derived from the underlying transitive structures by movement of the theme-object to subject position. This results in a sentence in which the theme is in a non-basic position, which, according to our theory, is harder to produce than a sentence in which the thematic roles are in their base-generated position, as in the transitive sentences used in the experiment. The findings are also in line with Kegl’s (1995) SEVEH and not contradictory to Thompson’s ASCH. The ASCH states that the number of arguments a´nd the complexity of the argument structure complicate the performance of Broca patients. The present data suggest that the complexity of the argument structure has a greater influence than the number of arguments: although the unaccusatives have only one argument and the transitives have two, the former is more difficult to produce. However, although both the SEVEH and the ASCH make the right predictions with respect to the current data, neither the SEVEH nor the ASCH predict the previously found problems in sentences with scrambled objects (Bastiaanse et al., 2003) and moved verbs and auxiliaries (Bastiaanse and Thompson, 2003). The SEVEH focuses on the order of the arguments, the ASCH on the argument structural properties of verbs. The DOP-H focuses on derived order of all
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constituents in the sentences and, therefore, covers problems with scrambled objects and moved verbs as well. It is interesting that the discrepancy between the production of transitive and unaccusative constructions observed in the Broca patients was not present in the group of fluent aphasic speakers. Similarly, Kegl (1995) did not find a discrepancy between the two sentence types in an anomic conduction patient. In a recent study, Bastiaanse and Edwards (2004) showed that the behaviour of a (Dutch and English) group of Wernicke patients was strikingly similar to that of a group of Broca patients on a test for filling in finite verbs and infinitives in sentences. For both aphasia types, filling in finite verbs was significantly more difficult than filling in infinitives, in either language, but the error types within the two groups were different. Bastiaanse and Edwards argued that if language breaks down, the same structures are vulnerable, although the level of breakdown clearly differs in the two aphasia types. Apparently, this does not hold for the present group of fluent aphasics. They are equally poor in constructing both types of sentences, even though the verb is given. They make a large number of errors that fall within the ‘other’-category; these are paraphasias, paragrammatic sentences and multiple errors. For them, constructing sentences in the unaccusative condition is not more difficult, but notice that it is not easier either, although fewer nouns need to be realized in the unaccusative sentences. Although we take the results in the Broca group as support for our hypothesis, there is an interesting alternative explanation that needs to be mentioned. It has been suggested that animacy plays a role in agrammatic comprehension and production: sentences with an inanimate subject might be difficult for Broca patients (Caplan, p.c.). However, both Saffran, Schwartz, and Marin (1980) and Menn et al. (1998) show that it is not inanimacy of the subject per se, but the combination of an inanimate subject with an animate object that influences the performance in Broca’s aphasia. If one assumes that animacy plays a role, the question remains why a superficially simple sentence with an inanimate subject is more difficult than a superficially more complex sentence with an animate subject in a grammatically impaired aphasic patient, but not in lexically-semantic impaired patients. In other words, what makes the inanimate subjects so difficult in a grammatical sense? We assume that it is only a particular class of sentences with inanimate subjects that poses problems for Broca patients and this is the class of sentences with derived inanimate subjects, such as passives (the car is sold by the nurse) and unaccusatives (the glass breaks). The DOP-H predicts that these sentences are difficult for Broca patients. Another alternative explanation is that the unaccusative variant might be less frequently used in Dutch. This is hard to evaluate, since frequency lists do not give any information about transitivity. Intuitively, however, the opposite seems to be true. For example, the bell is ringing, the butter melts, and the ball is rolling are more likely than he is ringing the bell, he is melting the butter and he is rolling the ball). Apart from that, one may wonder why frequency of special use of the verb would influence the behaviour in Broca’s aphasia but not in fluent aphasia. We therefore opt for a grammatical explanation: patients with Broca’s aphasia have problems with the construction of unaccusative sentences in which a verb with alternating transitivity is used, because the theme has to be moved from its underlying (object) position. Sentences in which the order of the constituents is derived are, in general, difficult to produce for patients who suffer from this aphasia type.
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Appendix A. Test items
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Transitive
Intransitive
De man rijdt auto The man is driving a cara De jongen smelt de boter The boy is melting the butter De man kookt soep The man is cooking the soup Het meisje speelt de plaat The girl is playing the record De vrouw breekt het glas The woman breaks the glass De jongen verbrandt het boek The boy is burning the book De vrouw verdrinkt de kat The woman is drowning the cat Het meisje draait de tol The girl is spinning the top De jongen scheurt het papier The boy is tearing the paper De jongen rolt de sneeuwbal The boy is rolling the snowball De pastor luidt de klok The priest is ringing the bell Het meisje lost de suiker op The girl is dissolving the sugar De jongen stuitert de bal The boy is bouncing the ball opa rookt een pijp Grandfather is smoking a pipe
de auto rijdt the car is driving de boter smelt the butter is melting de soep kookt the soup is boilingb de plaat speelt the record is playing het glas breekt the glass breaks het boek verbrandt the book is burning de kat verdrinkt the cat is drowning de tol draait the top is spinning de broek scheurt (lit.) the jeans are tearing de sneeuwbal rolt the snowball is rolling de klok luidt the bell is ringing de suiker lost op the sugar is dissolving de bal stuitert the ball is bouncing de pijp rookt the pipe is smoking
a
In the translations the gerund is given. However, Dutch has no gerund, all sentences have the form subject–finite verb–(object). b ‘to cook’ and ‘to boil’ are the same verb in Dutch: ‘koken’.
Appendix B. Individual scores Error type/
tr4unacc
Condition/
unac
tr
Subject unac
tr
Rest Unac
tr
unac
tr
Broca’s aphasia B1 B2 B3 B4 B5 B6 B7 B8
50 1 5 7 9 11 5 2 10
6
1
3 2
21 9 4 1 1
24 10 2 1 3
1
1
4
7
2
1
40 4 5 6 4 3 4 12 2
79 2 10 13 11 14 5 12 12
2
1 2 1
Correct
(continued on next page)
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Table (continued) Anomic/Wernicke aphasia
17
14
F1 F2 F3 F4 F5 F6 F7 F8
1 1 6 1 3
1 5 6
5
1 1
0
0
40
47
2 7 1
4 9 4
14 12 4
14 11 5
56
51
13 12 1 12 11 0 2 5
14 10 4 5 8 0 2 8
tr4unac: transitive instead of unaccusative sentence and the other way around; -subject: subject omission; rest: all other errors; trZtransitive, unacZunaccusative.
References Bastiaanse, R., & Edwards, S. (2004). Word order and finiteness in Dutch and English Broca’s and Wernicke’s aphasia. Brain and Language, 89, 91–107. Bastiaanse, R., Koekkoek, J., & Van Zonneveld, R. (2003). Object scrambling in Dutch Broca’s aphasia. Brain and Language, 86, 287–299. Bastiaanse, R., Rispens, J., Ruigendijk, E., Juncos Raba´dan, O., & Thompson, C. K. (2002). Verbs: Some properties and their consequences for agrammatic Broca’s aphasia. Journal of Neurolinguistics, 15, 239–264. Bastiaanse, R., & Thompson, C. K. (2003). Verb and auxiliary movement in Dutch and English agrammatic speakers. Brain and Language, 84, 286–305. Burzio, L. (1986). Italian syntax. Dordrecht: Reidel. Graetz, P., De Bleser, R., & Willmes, K. (1992). Akense Afasietest. Lisse: Swets and Zeitlinger. Grimshaw, J. (1987). In J. McDonough, & B. Plunkett, Unaccusatives: An overview. Proceedings of NELS 17, 1986, GLSA (1) (pp. 244–258). University of Massachusetts, 244–258. Kegl, J. (1995). Levels of representation and units of access relevant to agrammatism. Brain and Language, 50, 151–200. Lee, M., & Thompson, C. K. (2004). Agrammatic aphasic production and comprehension of unaccusative verbs in sentence context. Journal of Neurolinguistics, 17, 315–330. Levin, B. (1993). English verb classes and alternations: A preliminary investigation. Chicago: University of Chicago Press. Levin, B., & Rappaport-Hovav, M. (1995). The unaccusative hypothesis at the syntax-semantics interface. Cambridge, MA: MIT-Press. Menn, L., Reilly, K. F., Hayashi, M., Kamio, A., Fujita, I., & Sasanuma, S. (1998). The interaction of preserved pragmatics and impaired syntax in Japanese and English aphasic speech. Brain and Language, 61, 183–225. Saffran, E. M., Schwartz, M. F., & Marin, O. S. M. (1980). The word order problem in agrammatism: Production. Brain and Language, 10, 263–280. Thompson, C. K. (2003). Unaccusative verb production in agrammatic aphasia: The argument structure complexity hypothesis. Journal of Neurolinguistics, 16, 151–167.
Sentence production with verbs of alternating transitivity in agrammatic Broca’s aphasia Roelien Bastiaanse*, Ron van Zonneveld Department of Linguistics, Graduate School for Behavioral and Cognitive Neurosciences (BCN), University of Groningen, P.O. Box 716, AS 9700 Groningen, The Netherlands Received 23 April 2004; received in revised form 15 November 2004; accepted 15 November 2004
Abstract Bastiaanse, Koekkoek And Van Zonneveld (2003) hypothesized that individuals with Broca’s aphasia have problems with sentences in which the verb and its arguments are not in their base position. The present study is meant to test this hypothesis with the help of verbs with alternating transitivity: transitive: the boy breaks the glass; intransitive or unaccusative: the glass breaks. Superficially seen, the latter sentence is less complex (subject–verb) than the first (subject–verb– object), but from a theoretical point of view, the unaccusative reading (the glass breaks) is more complex, because the theme is in subject position, which is not the base position. A production test was presented to patients with Broca’s aphasia and with anomic/Wernicke’s aphasia, in which transitive and unaccusative sentences with the same verbs were elicited. The results show that broca patients are significantly better in producing the transitive sentences than the unaccusative ones, whereas there is no difference for the patients with anomic/wernicke’s aphasia. Furthermore, an error analysis reveals that the large majority of the errors made by the patients with Broca’s aphasia are transitive sentences while the picture depicts the unaccusative reading. This pattern does not occur in the patients with anomic/Wernicke’s aphasia. The results are taken as support for the hypothesis that sentences in which the verb and its arguments are not in their base position are difficult for patients with broca’s aphasia. q 2005 Elsevier Ltd. All rights reserved. Keywords: Broca’s aphasia; Agrammatism; Verbs; Unaccusatives; Transitivity; Word order
* Corresponding author. Tel.: C31 50 3635558; fax: C31 50 3634900. E-mail address: [email protected] (R. Bastiaanse). 0911-6044/$ - see front matter q 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jneuroling.2004.11.006
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1. Introduction The speech production of agrammatic Broca patients is characterized by so-called telegraphic speech, in which bound and free grammatical morphemes are frequently omitted or substituted. Several experiments have shown that both in comprehension and in production, Broca patients also encounter word order problems. Bastiaanse, Koekkoek, and Van Zonneveld (2003), Bastiaanse, Rispens, Ruigendijk, Juncos Raba´dan, and Thompson (2002) demonstrated that Dutch Broca patients have problems with sentences in which the verb or the object are not in their base position. This, together with the evidence from comprehension and grammaticality judgement experiments, led to the generalized hypothesis that all sentences with derived order are difficult to produce and comprehend in agrammatic Broca’s aphasia. This is called the Derived Order Problem Hypothesis (DOP-H). The general idea is that every language has a basic order, for example Subject–Verb–Object (SVO) for English and Subject–Object–Verb (SOV) for Dutch. All orders different from the basic order are derived and therefore, difficult to produce and comprehend/parse. For example, for Dutch, the DOP-H predicts that matrix clauses, in which the verb is in second position, are difficult. For English, yes/no questions, which are derived, since the auxiliary is before the subject, should be hard to produce. This was confirmed by a study of Bastiaanse and Thompson (2003). The present study focuses on sentences with derived subjects. The DOP-H predicts that these sentences will be hard to produce for Broca patients.1 1.1. Sentences with derived subjects: unaccusatives When ‘normal’ intransitive verbs are produced in sentences, the subject is often the agent, as in (1). These are so-called unergatives. There is another group of intransitive verbs, the so-called unaccusatives in which the subject of the sentence is not the agent, but the theme, as in (2). (1) the boy is speaking (2) the girl is falling It has been argued (see, for example Grimshaw, 1987; Levin and Rappaport-Hovav, 1995) that in sentences with an ergative verb, the subject originates as an object. Sentences such as (2) are thus derived from (3):
1 Note that the DOP-H only takes so-called overt movement into account and that, therefore, it is relatively independent from the often changing theoretical accounts within the Government and Binding (GB) framework. More recent theories also have the concept of covert movement, that is, non-visible movement. Hence, movement or merge operations that do not change the basic order are not supposed to be difficult for Broca patients. For example, in recent theories of GB, the subject is VP-internally generated and moves covertly to SpecIP. These kinds of covert movement are irrelevant to the DOP-H.
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A special group of verbs are those with ‘alternating transitivity’ (Levin, 1993), which can be used with either the agent or the theme in the subject position. When the agent is in subject position, the result is a transitive sentence, as in (4). When the theme is in subject position, this results in an unaccusative sentence, as in (5). Accordingly, verbs of this ‘break’-type must be analyzed as having one argument structure with two possible subcategorisation frames: one frame has an agent-subject and a theme-object, and one frame has a theme-object, that has been moved to subject-position. These structures will be referred to below as ‘the transitive reading’ and ‘the unaccusative reading’, respectively. Note that this analysis is reminiscent of (the second part of) Burzio (1986) generalization, stating that a verb which fails to assign accusative case fails to theta-mark an external argument. Hence the object is forced to move to the position of the external argument, the subject2. (4) the woman breaks the glass
Just like in (3), the theme in (5) is supposed to have been moved from an underlying object position. So, although (5) is superficially seen less complex than (4), in terms of linguistic theory (5) is more complex, because the subject is derived by object-to-subject movement. 1.2. Theories with respect to unaccusativity in relation to agrammatism There are several important theories with respect to the present study to the production of sentences with transitive and unaccusative verbs. The first one is from Kegl (1995) and called the Syntactically Enriched Verb Entry Hypothesis (SEVEH). This hypothesis predicts that any construction that requires movement of a noun phrase from one argument position to another, between d-structure and s-structure, such that the lexically specified arrangement of arguments would be permuted, will result in production problems. Another theory comes from Lee and Thompson (2004) and Thompson (2003) and is called the Argument Structure Complexity Hypothesis (ASCH). It states that verb complexity, either manifest as a high number of arguments associated with the verb, or a lack of direct mapping of verb arguments to sentence slots, renders verb (and thus sentence) production difficulty. This hypothesis predicts that verbs with one argument are more difficult to produce than verbs with two arguments and that (sentences with) unaccusative verbs are more difficult to produce than (sentences with) unergative verbs. This was confirmed in several experiments. The present study compares the production of verbs with alternating transitivity at the sentence level. We tested Dutch agrammatic speakers with Broca’s aphasia. 2 The first part of this generalization states that a verb which lacks an external argument fails to assign accusative case (Burzio, 1986, 178–179).
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In Dutch, the word order of the matrix clause is subject–finite verb–object. In the transitive condition, the agent is supposed to be in subject position and the theme in object position, whereas in the unaccusative condition the theme is supposed to be in the subject position. The SEVEH predicts that the transitive structure will be easier than the unaccusative structure. It is unclear what the ASCH predicts because the transitive version includes more arguments than the unaccusative one, but in the unaccusative sentences there is a lack of direct mapping. The DOP-H predicts, like the SEVEH that production of unaccusative structures is more difficult, because the theme is not in its basic position, as it is taken to be derived by object-to-subject movement.
2. Methods 2.1. Subjects We were primarily interested in the performance of individuals with Broca’s aphasia. In advance, six non-brain-damaged adult speakers were tested, to ensure that the items elicited the intended sentences. It was decided not to test a new control group of non-braindamaged speakers, but to use a control group of fluent aphasic speakers instead, as this might reveal more interesting results with respect to performance patterns. Eight patients with Broca’s aphasia and eight patients with anomic/Wernicke’s aphasia were tested. The aphasia type was established with the Dutch version of the Aachen Aphasia Test (AAT; Graetz, De Bleser, & Willmes, 1992) and confirmed by both the speech therapist and the examiner. The (spontaneous) output of the Broca patients was characterized by telegraphic speech. None of the Broca patients showed articulatory impairments that might have interfered with the test results. The production of both the anomic (nZ5) and the Wernicke’s (nZ3) patients was characterized by severe word finding difficulties and a limited number of paraphasias. The main difference between the patients with anomic and Wernicke’s aphasia was the degree of their comprehension deficit: auditory comprehension (as measured on the AAT) was more impaired in the Wernicke patients than in the anomic patients. All aphasic subjects were right-handed and aphasic due to a single stroke in the left hemisphere at least three months prior to testing. Relevant data are given in Table 1. 2.2. Materials In order to test the subjects’ ability to construct sentences with verbs in the transitive and unaccusative reading, a sentence elicitation task was developed. A picture was Table 1 Age (meanCrange), gender (mZmale, fZfemale) for the Broca’s and the anomic/Wernicke’s patients
Broca Anomic/Wernicke
Age
Gender
50.00 (20–68) 55.00 (31–70)
4 m, 4 f 5 m, 3 f
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Fig. 1. An example of the test. The verb in infinitive form is provided to the patient: luiden ‘to ring’.
presented to the patient with the intended verb (the infinitive) printed underneath. Only verbs with alternating transitivity were used. Pictures were drawn to elicit either a transitive or an unaccusative sentence. An example is given in Fig. 1 and the verbs are given in Appendix 1. Originally, the test contained 30 items, 15 transitive and 15 unaccusative. During the pilot period, however, when the non-brain-damaged speakers were tested, one item (to open) turned out to be difficult in the unaccusative reading (the door opens), so it was removed from the task. Therefore, the final task consisted of 14 verbs, each used twice, once in the transitive and once in the unaccusative condition (total 28 items). The order of the items was pseudo-random: seven items occurred first in the transitive condition, seven items first in the unaccusative condition. 2.3. Procedure and scoring Scoring was done both quantitatively and qualitatively. For the quantitative scoring a correct/incorrect system was used. A sentence was considered to be correct if it contained the required verb and thematic role(s) and if the thematic roles were in the required position. Some verbs allowed object omission in the accusative reading, for example, he is ringing and he is ringing the bell. Sentences with object omissions in this condition were counted as correct3, but omission of obligatory objects-for example, she breaks-was counted as an error. Omission of determiners was ignored. One construction was difficult to score: in Dutch the infinitive is in clause final position. If the (Broca) patients use an ellipsis, for example, klokken luiden ‘bells ringing’ it is unclear whether klokken ‘bells’ is in subject or object position. This happened only three times, in one patient, and it was decided to count these as correct in the unaccusative condition (the obligatory thematic role has been realized), but as incorrect in the transitive condition (the agent role is left out). 3 This happened only two times. Post hoc analysis with these items removed did not change the significance level.
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Since it was hypothesized that the unaccusatives were more difficult, this was also the most conservative way to score. For the qualitative analysis, a scoring system was developed post hoc on the basis of the most frequent errors produced by the Broca patients, since we were primarily interested in their error pattern. The following categories were distinguished: transitive/intransitive (the man cooks the soup/it cooks); intransitive/transitive (the ball rolls/he rolls the ball; the book burns/I burn the book); subject omission (he rings the bells/rings the bells; other (multiple errors, semantic paraphasias, nil reactions etc.).
3. Results 3.1. Quantitative analysis Since the groups of subjects are relatively small, statistical testing was done by using nonparametric tests. In Table 2, the results of the quantitative analysis are given for the two aphasic subgroups. The individual data are given in Appendix 2. For the Broca’s patients, sentence construction in the unaccusative condition is significantly more difficult than in the transitive condition (Wilcoxon, zZK1.995, pZ0.0499). For the anomic/Wernicke’s patients the unaccusatives are slightly easier, but this difference is not significant (Wilcoxon, zZK0.316, pZ0.789). 3.2. Qualitative analysis In Table 3, the results of the qualitative analysis are given (individual data in Appendix B). As can been seen from this table, the difference between the two conditions for the Broca patients is entirely caused by one error type: the production of a transitive sentence when an unaccusative sentence was supposed to be produced. Each of the Broca patients produces two or more of these errors and for seven of the eight Broca patients, it is the most frequent error in the unaccusative condition. Only the Broca patient with the lowest score produces more errors in the category ‘rest’. The data of the fluent patients show that this is not an artefact of the test: they produced transitives instead of unaccusatives as often as the other way around. This group makes many errors that do not concern argument structure, such as semantic paraphasias (for example, target: the glass breaks, realized: the drink will be broken) and paragrammatic sentences (target: the boy is tearing the letter, realized: Pete is going to tear4 on the letter). In sum, for the Broca patients, producing sentences in the unaccusative condition is significantly more difficult than in the transitive condition; when they make an error, the result is most often a sentence with an agent, that is, a transitive sentence. This difference between the two conditions is not found for the fluent patients. 4 In Dutch, this construction is ungrammatical not only because a PP instead of an NP is produced, but also because the future tense cannot be used to describe the picture (*de jongen zal aan de brief gaan scheuren).
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Table 2 Mean number correct (proportions correct) in the transitive and intransitive conditions for both aphasic subgroups
Broca’s aphasia Anomic/Wernicke’s aphasia
Transitive
Unaccusative
9.88 (0.71) 6.38 (0.46)
5.00 (0.36) 7.00 (0.50)
Table 3 Results of the error analysis (tr4unac: transitive instead of unaccusative sentence and the other way around; -subject: subject omission; other: all other errors; trZtransitive, unacZunaccusative) Error type/
tr4unac
Condition/
unac
tr
unac
Subject Tr
unac
Other tr
Broca Anomic/ Wernicke
50 17
6 14
1 0
3 0
21 40
24 47
4. Discussion It is hard for speakers with Broca’s aphasia to produce sentences in which the theme is in subject position, even though these sentences are expected to be less complex when only the surface structure is taken into account. In the unaccusative condition, only a subject and a verb need to be produced, whereas in the transitive condition an object must be realized as well. Notice that in the transitive condition, the object is hardly ever left out. Apparently, producing a simple S–Vfin–O sentence when the verb is given is not extremely difficult for this group of Broca patients. The results are in line with the DOP-H, which predicts that production (and comprehension) of sentences in which the word order is derived is impaired in Broca’s aphasia. According to Grimshaw (1987) and Levin and Rappaport-Hovav (1995), the unaccusative sentences as used in the experiment are derived from the underlying transitive structures by movement of the theme-object to subject position. This results in a sentence in which the theme is in a non-basic position, which, according to our theory, is harder to produce than a sentence in which the thematic roles are in their base-generated position, as in the transitive sentences used in the experiment. The findings are also in line with Kegl’s (1995) SEVEH and not contradictory to Thompson’s ASCH. The ASCH states that the number of arguments a´nd the complexity of the argument structure complicate the performance of Broca patients. The present data suggest that the complexity of the argument structure has a greater influence than the number of arguments: although the unaccusatives have only one argument and the transitives have two, the former is more difficult to produce. However, although both the SEVEH and the ASCH make the right predictions with respect to the current data, neither the SEVEH nor the ASCH predict the previously found problems in sentences with scrambled objects (Bastiaanse et al., 2003) and moved verbs and auxiliaries (Bastiaanse and Thompson, 2003). The SEVEH focuses on the order of the arguments, the ASCH on the argument structural properties of verbs. The DOP-H focuses on derived order of all
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constituents in the sentences and, therefore, covers problems with scrambled objects and moved verbs as well. It is interesting that the discrepancy between the production of transitive and unaccusative constructions observed in the Broca patients was not present in the group of fluent aphasic speakers. Similarly, Kegl (1995) did not find a discrepancy between the two sentence types in an anomic conduction patient. In a recent study, Bastiaanse and Edwards (2004) showed that the behaviour of a (Dutch and English) group of Wernicke patients was strikingly similar to that of a group of Broca patients on a test for filling in finite verbs and infinitives in sentences. For both aphasia types, filling in finite verbs was significantly more difficult than filling in infinitives, in either language, but the error types within the two groups were different. Bastiaanse and Edwards argued that if language breaks down, the same structures are vulnerable, although the level of breakdown clearly differs in the two aphasia types. Apparently, this does not hold for the present group of fluent aphasics. They are equally poor in constructing both types of sentences, even though the verb is given. They make a large number of errors that fall within the ‘other’-category; these are paraphasias, paragrammatic sentences and multiple errors. For them, constructing sentences in the unaccusative condition is not more difficult, but notice that it is not easier either, although fewer nouns need to be realized in the unaccusative sentences. Although we take the results in the Broca group as support for our hypothesis, there is an interesting alternative explanation that needs to be mentioned. It has been suggested that animacy plays a role in agrammatic comprehension and production: sentences with an inanimate subject might be difficult for Broca patients (Caplan, p.c.). However, both Saffran, Schwartz, and Marin (1980) and Menn et al. (1998) show that it is not inanimacy of the subject per se, but the combination of an inanimate subject with an animate object that influences the performance in Broca’s aphasia. If one assumes that animacy plays a role, the question remains why a superficially simple sentence with an inanimate subject is more difficult than a superficially more complex sentence with an animate subject in a grammatically impaired aphasic patient, but not in lexically-semantic impaired patients. In other words, what makes the inanimate subjects so difficult in a grammatical sense? We assume that it is only a particular class of sentences with inanimate subjects that poses problems for Broca patients and this is the class of sentences with derived inanimate subjects, such as passives (the car is sold by the nurse) and unaccusatives (the glass breaks). The DOP-H predicts that these sentences are difficult for Broca patients. Another alternative explanation is that the unaccusative variant might be less frequently used in Dutch. This is hard to evaluate, since frequency lists do not give any information about transitivity. Intuitively, however, the opposite seems to be true. For example, the bell is ringing, the butter melts, and the ball is rolling are more likely than he is ringing the bell, he is melting the butter and he is rolling the ball). Apart from that, one may wonder why frequency of special use of the verb would influence the behaviour in Broca’s aphasia but not in fluent aphasia. We therefore opt for a grammatical explanation: patients with Broca’s aphasia have problems with the construction of unaccusative sentences in which a verb with alternating transitivity is used, because the theme has to be moved from its underlying (object) position. Sentences in which the order of the constituents is derived are, in general, difficult to produce for patients who suffer from this aphasia type.
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Appendix A. Test items
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Transitive
Intransitive
De man rijdt auto The man is driving a cara De jongen smelt de boter The boy is melting the butter De man kookt soep The man is cooking the soup Het meisje speelt de plaat The girl is playing the record De vrouw breekt het glas The woman breaks the glass De jongen verbrandt het boek The boy is burning the book De vrouw verdrinkt de kat The woman is drowning the cat Het meisje draait de tol The girl is spinning the top De jongen scheurt het papier The boy is tearing the paper De jongen rolt de sneeuwbal The boy is rolling the snowball De pastor luidt de klok The priest is ringing the bell Het meisje lost de suiker op The girl is dissolving the sugar De jongen stuitert de bal The boy is bouncing the ball opa rookt een pijp Grandfather is smoking a pipe
de auto rijdt the car is driving de boter smelt the butter is melting de soep kookt the soup is boilingb de plaat speelt the record is playing het glas breekt the glass breaks het boek verbrandt the book is burning de kat verdrinkt the cat is drowning de tol draait the top is spinning de broek scheurt (lit.) the jeans are tearing de sneeuwbal rolt the snowball is rolling de klok luidt the bell is ringing de suiker lost op the sugar is dissolving de bal stuitert the ball is bouncing de pijp rookt the pipe is smoking
a
In the translations the gerund is given. However, Dutch has no gerund, all sentences have the form subject–finite verb–(object). b ‘to cook’ and ‘to boil’ are the same verb in Dutch: ‘koken’.
Appendix B. Individual scores Error type/
tr4unacc
Condition/
unac
tr
Subject unac
tr
Rest Unac
tr
unac
tr
Broca’s aphasia B1 B2 B3 B4 B5 B6 B7 B8
50 1 5 7 9 11 5 2 10
6
1
3 2
21 9 4 1 1
24 10 2 1 3
1
1
4
7
2
1
40 4 5 6 4 3 4 12 2
79 2 10 13 11 14 5 12 12
2
1 2 1
Correct
(continued on next page)
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Table (continued) Anomic/Wernicke aphasia
17
14
F1 F2 F3 F4 F5 F6 F7 F8
1 1 6 1 3
1 5 6
5
1 1
0
0
40
47
2 7 1
4 9 4
14 12 4
14 11 5
56
51
13 12 1 12 11 0 2 5
14 10 4 5 8 0 2 8
tr4unac: transitive instead of unaccusative sentence and the other way around; -subject: subject omission; rest: all other errors; trZtransitive, unacZunaccusative.
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