Are there constraints on childhood disfluency?

IOURNAL

OF FLUENCY

DISORDERS

6 (1981)

341

341-350

Disfluency?*

Are There Constraints on Childhood Nan E. Bernstein University

Boston

of the spontaneous

Analysis

children

reveals

moments

that

is constrained

children

experience

and eight

stuttering

constituent

normally normal

and

fluent

disfluent

(b) stuttering

type of constituent

(verb

A view of early stuttering

by normals.

disorder

and

structure,

with a particular

produced

and integration

stuttering

of both

breakdown

disfluently

planning

of eight

location

by sentential

fluency

phrase) not usually a sentence

speech

(a) the

as

is present.

INTRODUCTION

Bloodstein their

examined

(1974)

ers and noted utterances

stuttering However,

syntactic

be the result

motor

planning

in early

Earlier

components.

to be more

have investigated

as place in utterance (Soderberg, stuttered

1967;

Helmreich

number

of

and Bloodstein,

limitations,

generalizations

including

about sentence-level

1967)

their

Such

processing

inability

to discriminate

sentence-generation

between

process and linguistic

Soderberg,

suffer

from

a

to make significant constraints

be at play in the precipitation of stuttering on individual their

locus such a

parameters of

1967;

studies

inability

(p 3901.”

or word type most

and Gantwerk, 1973).

that

to evaluate

such linguistic

frequently

such

the syntactic

it difficult

disfluency

that

structures

or laborious

investigated

stutter-

to fragment

theorized

of syntactic

difficult

making

on (Bloodstein

appeared

He

of “attributes

stuttering,

studies

speech of preschool

of these children

few studies have systematically

of disfluency claim.

into

might

cause their

the spontaneous

that the stuttering

by-products

which

words,

may

as well as

of the

normal

behavior peculiar to stutter-

ing.

‘Paper Convention,

presented at the 1979 Atlanta,

annual

American

Speech

and Hearing

Association

November.

Address all correspondence to Nan E. Bernstein, Progray in Applied Psycholinguistics, Boston University, 605 Commonwealth Avenue, Boston, MA 02215.

OElsevier North Holland, 52

Vanderbilt

Ave.,

New

Inc., 1981 York NY

10017

0094-730X181104341-1082.50

342

Nan E. Bernstein

In order to construct more descriptively models

of stuttering,

it would

be useful

and explanatorily to more fully

adequate

describe

the

parameters governing the fragmentation of the young child’s utterance by stuttered incidents, and to compare such behaviors with those observed in the speech of normal children. designed to systematically stuttered

and fluent

hypothesis

For these reasons, the present study was

describe the distribution

speech. Specifically,

that the distribution

regulated,

as well

of such disfluency

as to account for fluency

sentence generation constraints

of disfluency

in early

the study sought to test the was syntactically

breakdown

in terms

of

of a temporal nature.

PROCEDURE Subjects through

were divided

into two groups-one

second-grade children

comprised

referred by Philadelphia

preschool screening programs for their stuttering of normally

fluent children,

from each stuttering

child’s

of preschool public school

behavior, and the other

matched for age and sex, randomly selected class. Children

suspected of expressive

or

receptive language delay or disorder were excluded from participation in the study. From an original group of 20 children followed, eight matched pairs were selected for the study described here. Each group consisted of two girls and six boys. The mean age of the stuttering group was 6-3, of the control group was 6-4 Children

that

yrs.

participated in an elicited

language procedure in which

they were required to assign captions to cartoon pictures. The task was embedded in a language Lotto format, in which children were required to label the pieces they drew in order to place them on their game board. Cartoon

scenes,

culled

characters familiar

from

comic

to all children

Tom and Jerry, and Dennis was random within

book covers,

depicted common

in the study, such as Mickey

the Menace. Whereas

Mouse,

picture presentation

the child’s set, the game itself was preset so that the

child always won the game. Sessions,

conducted

in

both

home

and school

settings,

were

taperecorded using a Nagra portable tape recorder and Beyer microphone. Transcriptions with hesitations,

were then made of all the children’s

repetitions,

prolongations,

Only full sentences-defined an identifiable

NP-Aux-VP

utterances,

and filled pauses noted.

for these purposes as those containing

sequence-generated

during the course of

Constraints on Disfluency

343

the game were analyzed. assistance or clarification.

Included

in the analysis

Instances of disfluency

were requests

for

for both groups were

considered in terms of their syntactic locus and were classified in terms of the word

involved,

prolongations, hesitations

in the case of full

and part-word

or the one that followed

and filled pauses, following

the incident,

the guidelines

repetitions

and

in the case of

used by Hawkins

(1971). Constituent

structures

phrase (NP,), auxiliary conjunction,

isolated for consideration

were subject noun

(Aux), verb phrase (VP), object noun phrase (NP,),

and complement.

Disfluencies

on the first word of such structures

occurring directly

(constituent-initial)

tallied. All other locations of disfluency

before or

were noted and

were termed midconstituent

lumped together as a single category for analysis,

and

regardless of part of

speech or position in the utterance, for purposes of statistical analysis. After the original transcripts

were compiled, a reliability

made in which an uniformed graduate student-not pathology-was scriptions

provided with the original,

check was

in the field of speech

unnotated tapes and tran-

of each child’s conversation. The student was asked to mark the

presence of all disfluencies test yielded a correlation

described above. Results

of the Spearman r

factor of 0.93 for repetitions,

tions, and 0.62 for prolongations,

all statistically

0.78 for hesita-

significant values for the

sample size under analysis. RESULTS An examination of the relationship the presence of stuttering

between initiation

or disfluency

of a constituent and

required some systemization

the varied types and quantities of verbalization

of

obtained from each child.

To provide a baseline on which to ascertain prevalence of disfluency or before constituent words

on

boundaries, tallies were made of the total number of

per corpus for each child and of the total number of possible

constituent

boundaries

constituent-initial hypothetical

words

present

in using

in corpus

the baseline

divided

obtained-total

by total words-against

corpus length of 100 words, to obtain disfluency

ments for both constituent-initial

a

measure-

occurrence and midconstituent

occur-

rence, which were then comparable across subjects. Two-way

ANOVA

in degree of disfluency

with repeated measures indicated that differences between the two groups were significant

(F =

344

Nan E. Bernstein

4.87; ~~0.05). disfluency

However, group placement failed to influence the types of

observed. There was no significant difference between stutter-

ers and their controls

in the proportion

(words or parts of words), use of filled

of hesitations,

repeated items

pauses, prolonged segments, or

revised sentences. A test of the behaviors themselves level of 0.01 (F = 12.46).

was significant

Scheffe multiple

comparisons

at a confidence were computed

and indicated that the single most frequent form of disfluency groups was hesitation.

For the control

behaviors was displayed significantly for the stutterers, significantly

of an F_,,,

each child’s quently,

more frequently than the others. But and word-level

more often than did other disfluent

Results indicating

both hesitations

test for homogeneity

proportioned

for both

group, none of the remaining

disfluency

repetitions

occurred

behaviors. of variance performed on

values yielded a value of 13.19,

that the variances were not, in fact, homogeneous. preliminary

assessment

the locus of disfluency nonparametric

of the effect of constituent

eliminated

earlier plans to use

tool, the Wilcoxon

Sign Test

Related Samples, was administered

Conse-

structure

for Differences

Between

in order to determine the significance

of the difference between the stutterers’

disfluency

words

tendency for disfluency

and midconstituent

words.

The

on constituent-initial

located on or just prior to the first word of a constituent, interspersed

among constituent

level of significance.

on

Instead, a

ANOVA.

components,

to be

instead of being

was significant

at the 0.01

The same procedure performed on the data of the

control group produced similar findings, at the 0.05 level of significance. Results of Mann-Whitney for stuttering

children

aries was significantly p
U-test analysis indicate that the tendency

to fragment utterances along constituent different

The disfluency

from

of these stuttering

strongly confined to a constituent-initial children.

However,

that of their children

bound(U

=

4;

was much more

locus than was found for normal

there was no significant

groups on frequency of disfluency

controls

difference between the two

located in the midconstituent

position

(U = 18; p>O.O8). Hence, the major difference between the two groups appears to be in the strength and quantity of constituent-initial A two-way specifically

ANOVA

the role played by constituent

ency locus. Results

disfluency.

with repeated measures was used to assess more structure

indicated an effect of constituent

in regulating disflutype, for example,

Constraints on Disfluency

345

NP,, Aux, VP (f = 16.81; p
However, there did not appear to be

between patterns of locus of fluency

speech group (F =

1.25;

p>O.O5).

appeared to experience disfluency

That

breakdown

is, both groups

and

of children

while producing the same select group

of sentence constituents. Scheffe analysis was used to examine the nature of this distribution of disfluency

across the constituent types (Table 1). Results of the analyses

indicate that the first noun phrase of the utterance (NP,) is the favored locus of disfluency

for both groups, followed

by and and verb phrase

(VP). None of the other possible loci were significantly frequent involvement of and primarily

represented. The

in connection with disfluency can be seen as

overlapping with the initiation

the tendency of the children

of the utterance, as in NP,, given

in the study to link full utterances with and.

In fact, the frequency with which and occurred as a sentence lead-in was so common that it was calculated independently

of all other conjunc-

tions. Thus, for the most part, it is difficult to separate disfluency occurring either

on and or on NP,

disfluency

as being indicative

of anything

more than

in attempting to utter the sentence.

However,

VP attracted a significantly

the young stutterers.

Disfluency

significantly

represented

implications

of this surprising

high degree of disfluency

on this particular

constituent

in the speech of the normal

for

was not

children.

The

finding are discussed below.

DISCUSSION The two purposes of this study were to explore (1) the hypothesis disfluency

in young stuttering

than randomly,

distributed

children

might be systematically,

among major

utterance; and (2) similarities

components

and differences

that rather

of the child’s

between productions

of

fluent and nonfluent utterances by young normal and stuttering children, to help isolate characteristics of normal sentence-planning Bloodstein’s

length, stuttering

selections

processes.

appears to be essentially

from

and structure children

incident than

hypothesis (1974) that there are syntactic constraints on

the locus of disfluency examine

more typical of the stuttering

spontaneous

correct, even when we

speech in which

of utterance differ.

Both

appear to chop up their

normal

utterances

vocabulary, speaking

with

and

disfluent

1

6.0

5.1

2.5

1.1

0.4 0.5 0.7 0.7

NP, VP and

Comple Other Aux PrepP Conj

Test Value p 0.05 (*) p 0.01 (**) Means

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

0.25 -

0.38

0.13

-

-

-

-

-

-

-

1.75

1.75

2.00

2.12

1.38 -

0.37

0.37

0.62

0.75

NP, 2.50

1.12

5.72 6.65

5.72 6.65 Conj

-

-

0.00 -

0.25

0.38

5.72 6.65 PrepP 0.75

Across Constituents

5.72 6.65 Aux 0.75

of Disfluency

5.72 6.65 Other 0.50

Comple 0.37

Standard Error = 0.98

NORMALS

Scheff;? Analysis of Distribution

TABLE

-

2.62 -

4.00

4.37

4.37

4.62

4.75

5.12

5.72 6.65 VP

-

0.88

3.50

4.88

5.25

5.25

5.50

5.62

6.00

5.72 6.65 and

1.07

2.75

5.37

6.75+*

7.12**

7.12**

7.50** 7.37**

7.87

NP,

5.72 6.65

2.5 3.7 4.5 4.6 4.7 6.2 12.1 12.4

Means

Comple Other Aux PrepP Conj NP, VP and

Comple 2.50 -

Standard Error = 1.59 Test Value p 0.05 (*I p 0.01 (**I

STUTTERERS

9.24 10.76 Other 3.75 1.25 9.24 10.76 Aux 4.50 2.00 0.75 9.24 10.76 PrepP 4.62 2.12 0.87 0.12 9.24 10.76 Conj 4.75 2.25 1.00 0.25 0.13 -

1.50

NP2

6.25 3.75 2.50 1.75 1.63

9.24 10.76

9.24 10.76 VP 12.12 9.62* 8.37 7.62 7.50 7.37 5.87 9.24 10.76 and 12.37 9.87* 8.62 7.87 7.75 7.62 6.12 0.25 -

9.24 10.76 NP, 16.37 13.87** 12.62** 11.87** 11.75** 11.62** 10.12* 4.25 4.00

348

Nan E. Bernstein

episodes at constituent counter fluency constituents The

boundaries,

breakdown

and neither

group appears to en-

the internal

structure

rank ordering

of constituents

noun

most frequently

phrase and the linking

children-that

represented as

behavior was identical for both groups, with conjunction

affected. It is solely the additional significant stuttering

of sentence

with any significant frequency.

locations for such disfluent the initial

within

of initiation

the pattern and degree of disfluent

and most often

point of disfluency

of verb phrase-that

for the

distinguishes

behavior observed in this structural

analysis. Similarity

can also be found in the types of disfluency

observed

between the two groups. When they did encounter periods of disfluency, both groups manifested essentially

similar

categories.

difference was often heard on the

However,

a qualitative

behavior in terms of rough

tapes between certain normal easy repetitions children’s analysis

and some of the stuttering

more tense and extended repetitions. of the type and distribution

similarities

than differences

Nevertheless,

of disfluency

careful

demonstrated

between young stutterers

more

and normal chil-

dren. The findings of this study indicate that the major point of disfluency for both groups of children unit. Thus, on linguistic

is the constituent

boundary, a grammatical

the theoretical notion of nodes, labeled NP, VP, and so forth, tree-structure

diagrams, appears to constrain the location of

disfluent episodes. It is the initiation

of the node under which lower-level

specific lexical items are subsumed that attracts speech difficulty. highest possible level of analysis and formulation, all-S is,

or sentence -that for

both groups

breakdown synonymous

attracts the greatest degree of disfluency.

of young

children,

in connected discourse with the initiation

Results

the major

is the first

point

noun phrase, which This

is

is a

as we would assume that major

demands occur just prior to the initiation

of previous studies of both children

that processing

That

of fluency

of the utterance as a whole.

perfectly logical and expected finding, processing

At the

it is the highest node of

of the sentence.

and adults strongly

suggest

of spoken language does appear to be by the clause,

rather than word by word, as was suggested in early associationist

models

of language (Maclay and Osgood, 1959; MacKay, 1970; Lindsley,

1975).

However,

speaking is often initiated

completed, especially

before all planning has been

planning of the VP (Lindsley,

1975,

1976). Thus,

on Disfluency

Constraints

points

349

of indecision

or,

less often, error

observed between such points of indecision groups

in this

planning

study strongly

of syntactic

suggests

strings,

are reached. The

similarity

reached within and between

levels

of strain

inherent

rather than any “attributes

in the

of syntactic

structures that cause their motor planning to be more difficult or laborious (Bloodstein,

1974,

p. 390)”

constant in the disfluency

That the constituent

categories remained

of both groups, while the parts of speech that

composed them and surrounding

constituents

varied from child to child

and sentence to sentence, strongly suggests that the process of integrating such structures

into meaningful

selves, is responsible

wholes,

and not the structures

them-

for the difficulty.

Such a view is given support by the special behavior observed in the stuttering

children-that

demonstrated

of disfluent

that, for adults,

before all information

initiation

sentence

of VPs.

production

Lindsley

(1975)

may be initiated

about the verb has been processed, and that “the

final stage of verb processing-the

retrieval of the name for the action-

will be assumed to occur after the initiation of the utterance (p. 333).” subsequent study, Lindsley

In a

(1976) attempted to parcel out the processing

demands for subjects and verbs in simple sentences produced by adults. He concluded that “subject phrases can always be counted on to provide at least a two-syllable

delay by their overt utterance, a delay which may

be generally sufficient

to permit enough verb information

assure fluency (p. 351).” forthcoming.

For the young stutterers,

We might hypothesize

processing to

such fluency was not

that these children require more time

to integrate the components of the various sentence constituents. then, should VPs be especially the simplest

troublesome?

utterance, the constraints

They

Why,

may reflect, even in

of number agreement imposed by

the preceding noun, the necessity of encoding semantic notions such as tense and aspect to be carried by the sentence as a whole. choice of verb will forcing within

Similarly,

constrain the succeeding elements of the utterance,

accommodations

to notions

of transitivity/intransitivity

the verb, as well as complement

given verb selection. Alternatively,

structures

coded

accepted or barred

the VP may simply

represent another

stepping stone to planning the completion of the utterance extending far beyond the scope of the verb. The advantage of midsentential

children

may simply

be taking

stopping points to contemplate the rest of the

utterance as a whole. The fact that stuttered incidents appear to be syntactically

governed

350

Nan E. Bernstein

in the speech of young children planning

suggests that it is higher-level

processes, and not word-,

considerations,

sound-,

that may act to precipitate

sentence-

or motor-gesture-specific the stuttered

moment.

In

addition, the finding that such patterns of disfluency are largely congruent with patterns of disfluency the preceding common

view,

noted in normal children

reinforces not only

but further suggests that fluency

childhood

process and

children and normal children

that differences

breakdown

between

may end up best explained

is a

stuttering

in terms of the

and not in terms of its precipitation.

manifest form of the disfluency,

REFERENCES Bloodstein, 0.

The

Disorders, Bloodstein,

rules

of early

O., and Gantwerk,

young

stuttering.

/ournal

of Speech

and

Hearing

1974, 39, 379-394.

children.

/ournal

6. Grammatical function in relation to stuttering in of

and

Speech

Hearing

Research,

1967,

10,

786-789. Hawkins,

P.R. The syntactic location of hesitation pauses. Language and Speech,

1971,14,277-288. Helmreich,

H.G.,

disfluency

and Bloodstein,

Hearing Research, Lindsley,

The

grammatical hypothesis.

factor

in childhood

/ourna/ of Speech

and

1973, 16, 73 1 - 738.

J.R. Producing simple utterances: How far ahead do we plan? Cognitive

Psychology, Lindsley,

J.R.

journal

1975,

7, l-19.

Producing

simple

of Psycholinguistic

H.,

and Osgood,

speech. Word, Soderberg,

G.A.

Research,

1959,

Linguistic

1967,

utterances:

Research,

McKay, D.C. Context-dependent Maclay,

0.

in relation to the continuity

stuttering.

C. Hesitation

Details

1976,

of the planning

process.

5, 331-353.

Kybernetik, phenomena

1970, 7, l-9. in spontaneous

English

15, 19-44. factors in stuttering.

lO, BOl-810.

/ournal

of Speech

and Hearing