Journal of Fluency Disorders

26 (2001) 179 ± 205

Stuttering and bilingualism

A review
John Van Borsel*, Elise Maes, Sofie Foulon
Ghent University Hospital, Ghent, Belgium
Received 9 November 2000; received in revised form 23 January 2001; accepted 1 March 2001

Abstract

Although stuttering in bilinguals is an area of interest to both clinicians and

researchers, data on bilingualism and stuttering are scanty. This paper reviews the
available literature on stuttering and bilingualism. Major findings are that stuttering is
probably more prevalent in bilinguals than in monolinguals, that stuttering can affect one
or both languages, that the two languages may be equally or differently affected, and
that diagnosis and treatment in bilingual stutterers seem to require a particular approach.
Educational objectives: The reader will learn about the prevalence of stuttering in
bilinguals. The reader will learn about and be able to describe the different patterns of
the manifestation of stuttering in bilinguals. The reader will learn about and know some
issues to consider in diagnosing and treating dysfluent bilingual clients. D 2001 Elsevier
Science Inc. All rights reserved.

Keywords: Stuttering; Bilingualism

1. Introduction

Stuttering in bilinguals is an area that has not received much attention. This is
rather remarkable in light of estimates that over 50% of the world's population is
bilingual (De Houwer, 1998) and that about 1% of the world's population stutters
(Bloodstein, 1995). Therefore, it is clear that many speech ±language pathologists

* Corresponding author. UZ Gent 2P1, De Pintelaan 185, B-9000 Gent, Belgium. Tel.: +32-9-
240-22-96; fax: +32-9-240-49-93.
E-mail address: john.vanborsel@rug.ac.be (J. Van Borsel).

0094-730X/01/$ ± see front matter D 2001 Elsevier Science Inc. All rights reserved.
PII: S 0 0 9 4 - 7 3 0 X ( 0 1 ) 0 0 0 9 8 - 5
180 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

have a fair chance of being confronted one day with bilingual individuals who
stutter. In providing services to bilingual individuals who stutter, clinicians may
be faced with unique problems and questions that go beyond their ordinary
competency with fluency disorders. For example, can one make a reliable and
valid judgement about the presence of stuttering in a language that is not one's
own language? Should one advise the parents of a bilingual child who stutters to
stop exposing the child to two languages until it has acquired good control over
one language? Is outcome of therapy in bilingual speakers worse than in
monolingual speakers?
Apart from its immediate clinical significance, the study of stuttering in
bilinguals is also interesting from a scientific and theoretical point of view. Many
so-called ``facts'' about stuttering and its development derive from studies of
monolingual speakers, virtually all of whom are English speakers, and have as yet
not been tested either crosslinguistically or within bilingual populations. Bern-
stein Ratner and Benitez (1985) suggested that bilingual stutterers may be ideal
clinical cases for testing the validity of models postulating that linguistic factors
play a role in the precipitation of stuttering moments. Bilingual cases allow the
study of whether presumed linguistically governed regularities in stuttering loci
and incidence remain constant regardless of language spoken. For example,
inconsistency of phonological loci across languages spoken by the same speaker
would seem to weaken purely motoric accounts of stuttering; consistency in
syntactic loci would appear to strengthen models that implicate a compromised
sentence planning component (Cabrera & Bernstein Rartner, 2000).
In spite of the potential significance for both clinicians and researchers, data
on stuttering and bilingualism are scanty, and systematic research of the relation
between both phenomena is rare. This article presents an overview of what is
currently known about stuttering and bilingualism. The prevalence and manifes-
tation of stuttering in bilinguals are discussed, as well as some diagnostic and
therapeutic issues. It is hoped that this information can help clinicians in their
assessment and treatment of bilingual clients and will provide researchers with
guidance for future research directions. One cautionary remark, however, is that
the literature on bilingualism and stuttering is quite diverse with regards to issues
such as number and age of subjects reported, language pairs involved, age of
language acquisition, proficiency and usage of both languages, and the method-
ology used in assessing stuttering, as well as bilingualism. Moreover, not all
sources give sufficient information to adequately judge their findings. Conse-
quently, the conclusions and generalizations formulated from this review must be
considered as tentative.
Unless otherwise stated, the term ``stuttering'' refers to the developmental
condition defined by the World Health Organization as ``disorders in the rhythm
of speech in which the individual knows precisely what he wishes to say but at
the time is unable to say because of an involuntary repetition, prolongation, or
cessation of a sound'' (World Health Organization, 1977, p. 202). As such,
stuttering is differentiated from normal dysfluencies and from dysfluencies like
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 181

hesitations and repetitions, whose origin is limited proficiency in a language. The

term ``bilingualism'' is used in its broadest sense, referring to a condition that
ranges from ``the total, simultaneous and alternating mastery of two languages''
to ``some degree of knowledge of a second language in addition to spontaneous
skills which any individual possesses in his (her) first language'' (Siguan &
Mackay, 1987, p. 13). By extension, ``bilingualism'' is used to refer to multi-
lingualism as well.

2. The prevalence of stuttering in bilinguals

Seeman (1974) pointed out that in early bilingualism, there is a higher risk for
stuttering to arise and referred to colleagues sharing this opinion, among whom
were Froeschels, Pichon, Borel-Maisonny, and Metreau. The belief that stuttering
is more prevalent in bilinguals than in monolinguals seems to be widespread
indeed (see, for instance, Eisenson, 1984; Karniol, 1992; Mattes & Omark, 1991;
Shames, 1989). One implication of this belief is the advice often heard not to
expose children to a second language until they have acquired good control of
their first language. However, few studies have actually calculated the prevalence
of stuttering in bilinguals, and these studies date to the first half of the previous
century. For example, Travis, Johnson and Shover (1937) surveyed public
schools in East Chicago, IN. A total of 4827 children (2405 boys and 2422
girls), ages 4 ±17 years (average 8;54 years), were interviewed at their respective
schools. Determination of whether or not stuttering was present was based on
reading and conversation. For non-English-speaking children, the help of an
interpreter was called upon. Overall, stuttering prevalence was 2.61%, but
prevalence was significantly lower in monolingual English-speaking children
than in those speaking one or two foreign languages in addition to English
(1.80% vs. 2.80% and 2.38%, respectively). A similar finding was reported by
Stern (1948) (cited in Bloodstein, 1995) who studied 1861 children in four
schools in Johannesburg, South Africa. In monolingual children, prevalence of
stuttering was 1.66%, however, in children who were bilingual prior to age six
years, stuttering prevalence was 2.16%. Moreover, three times as many bilinguals
as monolinguals were judged to evidence severe stuttering.
One drawback of studies like that of Travis et al. (1937), and perhaps also that
of Stern (1948), is that clinical judgements of the presence of stuttering were
based on a single assessment. In view of the well-known variability in symptoms
of stuttering across time and situation (Ingham & Costello, 1984), it can be
argued that single assessment is not a valid procedure. An alternative is to use
self-reports of stuttering in gathering prevalence data. One such study, an Internet
survey on bilingualism and stuttering (webpage: http://www.speech.psychol.
ucl.ac.uk./survey1/bilingual.html) was started only recently at University College
London (Au-Yeung, Howell, Davis, Charles, & Sackin, 2000). The survey asks
for personal information (gender, date of birth, ethnic background, occupational
182 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

background, educational level, . . .), language usage (when languages were

learned, proficiency level in the different languages used, proportion of language
usage), the environment under which the languages are used (including parental
usage), and the occurrence of speech disorders, in particular stuttering. Thus far
(last update May 2000), 794 responses have been received from 40 countries
around the world. The respondents, 656 (i.e., 82.62%) bilinguals and 138 (i.e.,
17.38%) monolinguals, reported 52 different mother tongues and 70 different
second languages. Preliminary results do not corroborate the findings of Stern
and Travis et al. The percentage of speakers reporting stuttering, either currently
or in the past, was almost identical among monolingual and bilingual speakers
(21.74% and 21.65%, respectively). As the authors themselves have pointed out,
there are pros and cons for conducting surveys on the Internet, and some biases
are unavoidable. One apparent bias in this study is that responses received, thus
far, were mostly from females. To what extent this preponderance of female
respondents influenced results is not clear. Considering the well-established male
to female sex ratio of about 3 to1 in stuttering (Bloodstein, 1995), it is a fact to be
kept in mind at any rate. Even more worrisome is the high ratio of respondents in
both groups (i.e., bilinguals and monolinguals) who reported a history of
stuttering. A lifetime incidence of 21% is much higher than that found in
previous studies, which mostly cluster closely around 5% (Bloodstein, 1995).
Of course, people are likely to seek out websites of their main interests or
concerns which may explain the elevated ratio of respondents who stuttered.
Another possibility, however, is that the high ratio may reflect a definitional
problem. Nowhere in this survey were respondents instructed which behaviors
should be considered as stuttering and which should not. They were asked only if
they ``ever experienced stuttering (stammering).'' It is conceivable, therefore, that
a number of respondents may have confused stuttering with other forms of
dysfluency (normal childhood nonfluency, language formulation problems,
cluttering). Regardless, the large difference between the incidence found in this
study and that of previous studies compels that caution be used in interpreting
this survey's findings and suggests that self-reports may not be more valid than
single assessments.
Except for the results reported by Au-Yeung et al. (2000), the available data
suggest that stuttering is more prevalent among bilinguals than among mono-
lingual speakers. One may wonder, then, how a higher prevalence of stuttering
among bilinguals may be explained. The data of Travis et al. (1937) suggest that
there might be a direct link between bilingualism and stuttering, at least in some
subjects. For 26% of the bilingual stutterers in their study, the age of onset of
stuttering coincided with the introduction of a second language. Indeed, some
authors seem to assume that bilingualism is directly at the origin of the fluency
disorder. Pichon and Borel-Maisonny (1964), for instance, mention that stutter-
ing could be ascribed to bilingualism in 25 (i.e., 14%) of the stutterers they
studied. In addition, Karniol (1992), who reported stuttering in a Hebrew ±
English-speaking child in an article entitled ``Stuttering out of bilingualism,''
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 183

seems to assume a direct link between the occurrence of stuttering and

bilingualism. She suggested that stuttering in this case was a function of syntactic
overload and referred to the neuroscience model of stuttering proposed by
Nudelman, Herbrich, Hoyt, and Rosenfield (1989) to account for it. Briefly,
this model proposes that dysfluencies reflect moments of instability in a multi-
loop system. Speech motor control involves two major control loops, an outer
loop for ideation and linguistic programming and an inner phonatory loop for
motor programming of the vocal apparatus. Bilingualism, then, leads to insta-
bility as a result of the additional processing time required for either the outer
loop, inner loop, or both. Another theory that Karniol considered but dismissed
because of doubts about its scientific usefulness is Starkweather's (1987)
Demands and Capacities model. According to this model, stuttering occurs
when a child lacks the capacities to meet fluency demands. One could assume
that, in the case of stuttering in bilingual children, using two languages places
demands on them that exceed their capacities.
Some caution is needed, however. Travis et al. (1937) noted with respect to
their own findings that one cannot attribute differences in prevalence of stuttering
between monolinguals and bilinguals solely to bilingualism. Other factors they
considered, which may have played a role, were the economic insecurity and
emotional instability found in many foreign homes and the confusion resulting
from being placed in a strange and new environment during the process of second
language acquisition. Travis et al. stressed that the observed difference between
bilingual and English-speaking subjects may have limited significance, because it
was a very small difference and the fact that 97.20% of the bilinguals did not
stutter should not be overlooked. The possibility that being placed in a novel
situation may be a contributing factor in some cases of bilingual stutterers was
also noted by Mussafia (1967) in discussing the occurrence of speech and
language disorders among children of foreign mine workers in the Borinage,
Belgium. According to Mussafia, stuttering and other speech and language
disorders arise when children must change abruptly from one language to another
upon their arrival in a new country. Less talented children in particular would
have more difficulty in adapting, and Mussafia felt that they had a higher risk of
becoming anxious and demonstrating speech and language disorders.
It should also be noted that these three studies (Karniol, 1992; Mussafia,
1967; Travis et al., 1937) may involve two different types of bilingualism.
Karniol (1992) described a case of simultaneous bilingualism, whereas Mussa-
fia (1967) and Travis et al. (1937) discussed consecutive bilingualism. In
simultaneous bilingualism, a child learns two languages from birth onwards. In
consecutive bilingualism, a second language is introduced after a child has
already mastered to some degree a first language. It may be that the factors
contributing to the more frequent occurrence of stuttering in bilinguals differ for
these subtypes of bilingualism.
Lebrun and Paradis (1984) pointed out yet another factor that could contribute
to the development of stuttering in bilinguals. They stressed the importance of the
184 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

linguistic input to bilingually raised children. In particular, they suggested that the
input of linguistically mixed utterances might trigger the development of
stuttering in bilingual children with a predisposition to stuttering. Based on the
finding that monolingual stutterers not infrequently mix two synonymous words
or phrases, it was hypothesized that speech production is impeded in stuttering
children, because they find it difficult to select only one of two equivalent
linguistic items crossing their mind. This difficulty would be increased when two
languages are used quasisimultaneously.
Interestingly, Agius (1995), compared the language skills of a bilingual
Maltese ± English stuttering child aged 6;9 years and an age-matched Maltese ±
English nonstuttering child of similar sex and comparable socioeconomic back-
ground, academic performance record and place in family and found a higher
percentage of mixed utterances in the stuttering child. Moreover, an analysis of
the loci of dysfluencies in the stuttering child showed that stuttered dysfluencies
in this child's speech far more often preceded mixed utterances than did normal
dysfluencies, 48.7% vs. 17%, respectively. According to the author this might
have reflected the child's difficulty in differentiating between Maltese and
English lexicals. Although the study of Agius was limited to the comparison
of one stuttering and one nonstuttering bilingual child, its findings are still
interesting. In addition, Cabrera and Bernstein Ratner (2000), who studied a 5-
year-old Spanish ± English bilingual boy, reported an association between code-
switching events and the occurrence of fluency failures. They mentioned that
some of his code-switching events attracted stutters. It is not clear, however,
whether this child really demonstrated a stuttering disorder. The authors felt that
the majority of this child's dysfluencies could be due to language formulation
rather than stuttering. On the other hand, in a case study reported by Shenker,
Conte, Gingras, Courcey, and Polomeno (1998), examination of the mixed
utterances of a French ±English-speaking preschool child, did not suggest an
increase in stutter-like dysfluencies. Nonetheless, it was noted that code mixed
utterances were later substituted for word finding difficulties, in which inter-
jections would have been used at an earlier stage.
Clearly, the relationship between dysfluencies and mixed utterances in
bilingual stutterers deserves particular attention and needs further investigation.
If bilingual children who stutter are found to have a higher number of code-
mixed utterances than nonstuttering peers and a tendency for dysfluencies to
occur primarily in association with code mixed utterances, the causal link
between bilingualism and the occurrence of stuttering, as was suggested by
Karniol (1992) and Pichon and Borel-Maisonny (1964), would seem more likely.
On a practical level, this could justify the clinical practice of temporarily
deferring or eliminating bilingual education of children at risk for stuttering.
On a theoretical level, a functional association between the loci of stuttering
moments and code mixing would support the role of language encoding
difficulty in stuttering onsets (Cabrera & Bernstein Ratner, 2000). It has been
reported (Redlinger & Park, 1980) that code mixing in young bilinguals is a
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 185

function of linguistic proficiency. Higher frequencies of mixing are seen during

the earliest stages of bilingual development, which decrease with advancing
linguistic abilities. However, there is also the possibility of an alternative
interpretation of the eventual association between code mixing and the occur-
rence of stuttering in bilingual children. As suggested by Karniol, code mixing in
bilingual stuttering children could be a strategy to cope with dysfluencies. She
interpreted her data as indicating that switching from one language to another in
midsentence was a way of coping with blocking. It is not clear if the dysfluencies
in mixed utterances of bilingual children who stutter always precede instances of
code mixing rather than follow them. If so, this would support the interpretation
of mixed utterances being used as coping strategies. Assuming that code mixing
is a strategy that bilingual children adopt to escape or avoid dysfluencies,
temporarily withholding such children's exposure to a second language as a
therapeutic measure might not be indicated.
Another point that awaits further investigation is whether or not prevalence of
stuttering in bilinguals is affected by the similarities of the languages involved.
For example, is stuttering prevalence higher in individuals speaking two
linguistically related languages than in those who speak two totally different
languages? It is conceivable that closely related pairs of languages (e.g., a
standard language and its regional variety) may produce more confusion and,
therefore, more dysfluencies than more different pairs. However, it could also be
that nonrelated pairs demand more resources in learning two different lexical and
syntactic systems and cause more dysfluencies for that reason. The finding that a
linguistic variable, such as the similarity of the languages involved, is a factor in
the prevalence of stuttering in bilinguals, whatever the direction the effect, would
support the linkage of bilingualism to the occurrence of stuttering. Unfortunately,
the available data do not provide an answer to that question.
Still another factor warranting further investigation is the relation between the
prevalence of stuttering and the age at which the second language is acquired. Of
the bilinguals surveyed by Au-Yeung et al. (2000), ``middle'' bilinguals (i.e., those
who started second language acquisition between ages 7 and 12) stuttered less often
than did ``early'' bilinguals (i.e., second language acquisition between 0 and 6
years) or ``late'' bilinguals (i.e., second language acquisition after age 12). Within
the group of early bilinguals, those who started second language acquisition around
age 3 stuttered more often than other age groups. Differences were only significant,
however, for females, not males. Notwithstanding the possibility that some survey
respondents may have confused stuttering with normal nonfluencies, these data
raise an important issue. It seems that younger children are especially vulnerable to
developing stuttering if they are exposed to two languages. Likewise in the study
by Stern (1948) (cited in Bloodstein, 1995), the bilingual subjects who had a higher
prevalence rate of stuttering than did monolingual speakers, had been bilingual
prior to the age of 6 years. Most studies of stuttering in bilinguals have described
subjects who were exposed to more than one language from birth onward. It is also
interesting to note that stuttering onset, as far as we know, has never been reported
186 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

in adults learning a second language. The reasons for adult second language
learners' apparent ``immunity'' to developing stuttering are not clear.
There is a good deal of controversy in the literature on second language
acquisition concerning whether or not language acquisition in adults differs from
that in children (Larsen-Freeman & Long, 1991). Some claim that second
language acquisition is the same process irrespective of whether the learner
begins as a child or an adult, whereas others believe that children and adults go
about acquisition differently. One difference that could influence the likelihood of
developing stuttering concerns brain organization. Recent findings from brain
imaging studies indicate that age of acquisition is a major factor in the cortical
organization of second language processing. Kim, Relkin, Lee, and Hirsch (1997)
obtained functional magnetic resonance images (fMRI) of six late bilinguals (i.e.,
exposure to a second language in early adulthood) and six early bilinguals (i.e.,
exposure to two languages during infancy) during silent, internally expressive
linguistic tasks (i.e., describing events that occurred during a specified period of
the previous day). Ten languages were represented. All subjects reported
approximately equal fluency and frequency of usage in each language at the
time of testing. Kim et al. (1997) found that second languages were spatially
separated from native languages within Broca's area in the late bilinguals,
whereas native and second languages tended to be represented in common
frontal cortical areas in the early bilinguals. The regions activated within
Wernickes' area by the native and second languages overlapped in both groups,
regardless of the age of second language acquisition. Similarly, Dehaene et al.
(1997) found distinct cortical areas associated with native and second languages
in late bilinguals for language comprehension. Using fMRI, they assessed cortical
representation of language comprehension processes in eight fluent French±
English bilinguals. All subjects had French parents, and none had been exposed
to English before age seven. Listening to stories in French always activated a
similar set of areas in the left temporal lobe, clustered along the left superior
temporal sulcus. Listening to stories in English, however, activated a highly
variable network of left and right temporal and frontal areas, which were
sometimes restricted to right-hemispheric regions.
Why distinct cortical areas are activated by native and second languages in late
bilinguals is not clear. Kim et al. (1997) hypothesized that once cortical
representations of languages are formed by exposure early in life, they are not
modified subsequently, making it necessary to utilize adjacent cortical areas for
second languages learned later in life. As far as stuttering in bilinguals is
concerned, the finding that the same brain areas are recruited for learning and
processing both languages in early bilinguals whereas multiple and variable and
different areas are recruited in late bilinguals is particularly interesting at any rate.
One could hypothesize that early bilinguals are more vulnerable to stuttering
precisely because the same brain structures are utilized for learning both
languages, and stuttering reflects a functional overload of these structures. Late
bilinguals or adults learning a second language, in contrast, would be far less
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 187

prone to stutter because different structures are recruited for the second language.
Moreover, this hypothesis seems to fit well with recent brain imaging findings in
stutterers suggesting the possibility of a left hemispheric dysfunction in devel-
opmental stuttering. In several studies, an absence of the normal pattern of
hemispherical dominance for language in stutterers has been reported (Braun &
Ludlow, 1995; Braun et al., 1997; Fox et al., 1996; Kroll, De Nil, Kapur, &
Houle, 1997; Pool, Devous, Freeman, Watson, & Finitzo, 1991; Wu et al., 1995).
It should be noted, however, that age of acquisition may not be the only
determinant of the cortical representation of a second language. A series of
experiments using positron emission tomography (PET) by Perani et al. (1996,
1998) in Italian ± English bilinguals yielded quite different patterns of cortical
activity for each language in low language proficiency subjects but not in high
proficiency subjects, regardless of the age of acquisition of the second language.
The authors concluded that proficiency may be more important than age of
acquisition in determining the cortical representation of a second language.
Although Dehaene et al. (1997) found distinct cortical areas associated with
native and second language comprehension in late bilinguals, there was also
considerable intersubject variability in the areas activated while listening to the
second language, with some subjects showing similar activation foci for both the
native and second language. Dehaene et al. suspected that, in addition to age of
onset of second language acquisition, such variability among subjects might be
due to the specific conditions under which the second language was learned (e.g.,
different methods of teaching might favor different strategies for language
processing and hence distinct cerebral circuits) or to an intrinsic difference in
brain organization. Perhaps future brain imaging studies of bilingual stutterers
will help solve the question why younger children are especially vulnerable to the
development of stuttering if they are exposed to two languages.

3. The manifestation of stuttering in bilinguals

If a bilingual speaker stutters, how then does the stuttering manifest itself ?
Nwokah (1988) proposed at least three theoretical possibilities. One possibility is
that stuttering occurs in one language but not the other. Another possibility is that
stuttering occurs in both languages with speech behavior patterns that are similar
in each language, which Nwokah referred to as the same-hypothesis. Or stuttering
could occur in both languages but vary from one language to another. The latter
possibility was called the difference-hypothesis.

3.1. Stuttering occurs in one language but not the other

With respect to the possibility that stuttering occurs in one language and not in
the other, Nwokah (1988) suspected that this would be unusual. She studied 16
bilingual stutterers from Anambra state, Nigeria, speaking Igbo (a Nigerian
188 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

Table 1
Summary of the literature reporting cases of stuttering in bilinguals including a comparison of the
stuttering in both languages

No. of Age of the

Source Languages involveda subjects subject(s)
Van Riper, 1971 Eskimo/English 1 ?
Van Riper, 1971 English/Pahlevib 1 ?
Van Riper, 1971 Japanese/English/German 1 ?
Dale, 1977 Spanish/English 4 13 years (average)
Nwokah, 1988 Igbo/English 16 16 to 40 years
(mean 24;3 years)

Jarayam, 1983 Kannada/English 10 19 to 32 years

(mean 25;6 years)
Bernstein Ratner & Spanish/English 1 50 years
Benitez, 1985

Lebrun et al., 1990 French/Dutch 1 58 years

Jankelowitz & Bortz, English/Afrikaans 1 63 years
1996

Shenker et al., 1998 English/French 1 2 years 8 months

Cabrera & Bernstein Spanish/English 1 5 years
Ratner, 2000
Scott Trautman & Spanish/English 1 20 years
Keller, 2000
a
Language in italic is the predominant language. Both languages in italic indicates equal usage.
No indication means absence of information.
b
We assume that English was this person's first language as English is the official language in
Pakistan, but the text is not clear in this respect.

language) and English. None of these subjects stuttered in one language only.
This led Nwokah to conclude that bilinguals who stutter in one language and not
the other, if such persons exist, may be bilinguals who are far more dominant in
one language than another.
Table 1 provides an overview of the literature on stuttering in bilinguals. Only
those reports that included a comparison of the stuttering in both languages are
listed. As can be seen bilingual persons who stutter in one language and not the
other are, indeed, rather exceptional.
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 189

Manifestation of stuttering
In two (or more) languages
Only in one Similar Different pattern
language pattern
English
English
+
Spanish
Overuse of fillers such as ``er'' or ``mm'' common in
English but absent in Igbo
In English initial consonants more frequently stuttered
upon than vowels, in Igbo the opposite pattern
More stuttering in Kannada than in English, particularly
in spontaneous speech
Twice as dysfluent in English as in Spanish
More likely to have difficulty in initiating sentences or
clauses in Spanish than in English. Initial noun phrases
attracted as much dysfluency as did verbs in English
but were not a large source of dysfluency in Spanish.
Conjunctions and clause introducers seemed to attract
twice as much dysfluency in Spanish as in English
+
Stuttered less in English
More aware of his stuttering in Afrikaans than in English
A greater adaptation effect in Afrikaans than in English
A greater consistency in English than in Afrikaans
Predominantly more typical than less typical disfluent
behaviors in Afrikaans than in English
More stuttered like disfluencies in English than in French
Higher proportion of stutters on reflexives in Spanish;
higher rate of stuttering on adjectives in English
More stuttering in Spanish than in English

Van Riper (1971) quoted E. Douglas, a Canadian psychiatric social worker,

who visited the Southampton Island's Eskimo population and reported that none
of the Southampton population at that time stuttered ``except for the Hudson Bay
Company Clerk who stutters in English but not in Eskimo.'' Van Riper also
included an excerpt from a letter by a Pakistani stutterer who wrote: ``You see I
am a Parsi by faith and our Holy Book is written in very old `Pahlevi Script.'
Now naturally, when I read our holy book, I never can understand a word of the
script and incidentally I rarely stammer while reading it.''
190 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

Apart from these anecdotal remarks, there is, to the best of our knowledge,
only one other reference to language-specific stuttering. Dale (1977) studied four
Cuban± American male adolescents (average age 13 years), all of whom were
born in the United States but spoke only Spanish at home. Each of the four
subjects was reported to have begun to stutter in Spanish within a year of
assessment. Whether or not there was a family history of stuttering in any subject
is not clear. All four subjects were quite proficient in Spanish and English, but
none of them exhibited dysfluent speech while speaking English. While con-
versing in Spanish, however, varying degrees of dysfluency were observed.
According to Dale, sociological and cultural factors played a major role in the
development of this pattern. It appeared that the boys were subjected to extreme
pressure by their Cuban ±American community to retain their knowledge of
Spanish and to speak it without error. Dale assumed that these boys' stuttering
originated during the Americanization process when they began to forget some of
their Spanish vocabulary. As they groped for appropriate Spanish words, the boys
demonstrated normal dysfluencies. These were identified as stuttering by their
parents. It was hypothesized that the pressure to speak Spanish fluently induced
fear in the boys, leading to further dysfluency in Spanish.
The cases reported by Dale (1977) and the case of the Pakistani stutterer
quoted by Van Riper (1971) seem to confirm Nwokah's assumption that language
specific stuttering occurs in association with an unbalanced language proficiency.
The subjects in Dale's study were more proficient in English than Spanish and
were beginning to forget some of their Spanish vocabulary. The subject quoted by
Van Riper was also more dominant in one language than in the other. He could
read Pahlevi script but did not understand it. Remarkably enough, the latter
subject stuttered in the language he was most familiar with, whereas the opposite
pattern was seen in the Cuban subjects reported by Dale. In searching for a
possible explanation for this apparently contradictory pattern, one should
remember that the stuttering histories of the subjects in Dale's study differed
from that of the Pakistani stutterer quoted by Van Riper. The subjects in Dale's
study did not stutter until the demands for fluent Spanish arose, whereas the
subject quoted by Van Riper reported that he does not stutter in one particular
condition, when reading a language that he does not understand.

3.2. Stuttering occurs in both languages: the same-hypothesis

When a bilingual person stutters, it is apparently far more common that he or she
stutters in both languages. In accordance with the same-hypothesis formulated by
Nwokah (1988), some individuals seem to show a similar speaking pattern in both
languages. One such case was cited by Van Riper (1971). A Japanese stutterer
communicated that he had exactly the same fears of Japanese sounds than he had of
English sounds and that, when he learned German, he also had the same fears of
German sounds that he had of Japanese sounds. Another case consistent with the
same-hypothesis was described by Lebrun, Bijleveld, and Rousseau (1990). Their
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 191

patient, a right-handed French ± Dutch-speaking male, began to stutter following

brain damage. Authors reported that the severity of his speech impediment
fluctuated but never disappeared and ``affected his French and Dutch equally''
(p. 255). It is important to stress that the latter case's stuttering was associated with
acquired neurological disease. The literature suggests that stuttering of neurogenic
origin may be more pervasive than developmental stuttering, and tends to occur
across all speech tasks (Ringo & Dietrich, 1995). Perhaps the case described by
Lebrun et al. (1990) should be considered in light of this.

3.3. Stuttering occurs in both languages: the difference-hypothesis

Bilingual stutterers who are dysfluent in both languages more often show
different patterns in one language than in the other. A number of authors have
reported cases that are consistent with Nwokah's (1988) difference-hypothesis,
including Nwokah herself.
Jarayam (1983) studied 10 bilingual male stutterers, ages 19 ±32 years (mean
25;6 years) who knew both English and Kannada, a language spoken in South
India, but Kannada was their primary language. There appeared to be no
difference in the two languages in either the pattern or distribution of stuttering
on different sound groups, however, subjects were reported to stutter more in
Kannada than in English, particularly in spontaneous speech, though this differ-
ence may not have been statistically significant.
This study (Jarayam, 1983) suggests that some bilingual stutterers may differ
in the severity of their stuttering in both languages, but not in the pattern or
distribution of stuttering. A case reported by Shenker et al. (1998) seems to
confirm this possibility. Shenker et al. studied the impact of bilingualism on
developing fluency in an English ±French-speaking preschool-age girl. Observa-
tions of the girl's interactions with her parents on in-clinic and out-clinic video
tapes indicated that English was her predominant language. A dysfluency
analysis of transcripts of the girl's spontaneous speech samples using the
CHILDES system coded the frequency and type of dysfluencies according to
guidelines proposed by Bernstein Ratner, Rooney, and MacWhinney (1996), and
revealed more stutter-like dysfluencies in English than in French (13.51% and
9.89%, respectively). Analysis of the loci of stuttering, classified according to
type of dysfluency, placement of stuttered word in a sentence, and word length,
found no significant differences between English and French. More word
repetitions were noted in French and more part-word repetitions in English, but
this reflected the girl's uneven language development in English and French.
There was a higher frequency of monosyllabic words in French in the sample,
hence more word than part-word repetitions.
Although similar patterns and distributions of stuttering but different degrees of
stuttering severity in each language does occur in bilingual stutterers, it is more
common to find that both the severity and distribution of dysfluencies differ from
one language to another. Thus, Bernstein Ratner and Benitez (1985) described a
192 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

50-year-old adult male bilingual stutterer who had spoken Spanish and English
since learning to speak and used both languages almost equally. He also had
stuttered in both languages since learning to speak. Although the clinicians and the
subject thought that his fluency was equally compromised in English and Spanish,
an analysis of spontaneous speech samples showed that he was almost twice as
dysfluent in English as in Spanish. He had more difficulty initiating sentences or
clauses in Spanish than in English, and his initial noun phrases attracted as much
dysfluency as did verb phrases in English, but they were not a large source of
dysfluency in Spanish. In addition, conjunctions and clause initial words seemed
to attract twice as much dysfluency in Spanish as in English. A phonemic analysis
showed that there was a tendency for fluency breakdown to occur on vowel-
initiated words in both languages but that Spanish vowels were represented almost
twice as often. The authors could not find account for the difference as to severity
of the stuttering, however, the differences in the loci of dysfluencies across the two
languages were believed to be associated mainly with differences between English
and Spanish sentence structure. Evidence that sentence structure may influence the
loci of stuttering, was also seen in a case reported by Cabrera and Bernstein Ratner
(2000), a 5-year-old Spanish ±English bilingual boy. He demonstrated higher
proportions of dysfluencies on reflexives in Spanish, and higher proportions on
adjectives in English. The authors suspected that differences in sentence structure
were at the origin of these findings. Spanish reflexives are word-initial rather than
word-final as in English, and English adjectives precede, rather than follow the
nouns they modify as in Spanish. The boy's overall degree of dysfluency in each
language was not reported.
Nwokah's (1988) analysis of the stuttering behaviors of 16 high-school-
educated bilingual stutterers in Anambra State, Nigeria, found a difference in
both the nature and severity of the stuttering. The subjects in this study (four
women, twelve men between 16 and 40 years) were said to be equally competent
in Igbo and English and to use both languages daily. Yet, all but one stuttered
more in one language than the other (either English or Igbo) in both spontaneous
speech and reading. Comparison of the fluency failures showed that an overuse of
fillers such as ``er'' or ``mm'' was common in English, whereas these did not
occur in Igbo. In addition, English-initial consonants were more frequently
stuttered than were vowels, whereas the opposite pattern was seen in Igbo. All
of the stutterers in this study were fully aware of which language they stuttered
the most. Subjects' explanations for the imbalance in the severity of their
stuttering behavior were that English was easier to speak because it needed more
planning and anticipation, or that it was harder for the same reason and, therefore,
less spontaneous. Nwokah believed that there are two bases for there to be more
stuttering in English in some subjects and more in Igbo in others. Referring to
Fiedler and Standop's (1983) neuropsychological model of the origin and
maintenance of stuttering and to the observations of Krashen and Pon (1975)
on monitoring in second language acquisition, Nwokah proposed that the
monitoring system involved in monitoring stuttered speech is the same system
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 193

that monitors second language production. This monitoring system would act as
an inhibitor for some subjects, creating a conscious control of stuttering behavior,
thereby reducing the frequency of stuttering. For others, it would act as an
activator, introducing tension and anticipation and increasing stuttering. In
addition, sociopsychological aspects appeared to play an important role. Nwokah
reported a trend for subjects to stutter most in the language with which they had
had more negative experiences at home or school.
Another study that reported a difference in both the nature and severity of
stuttering in a bilingual speaker is that of Jankelowitz and Bortz (1996). They
studied the fluency failures of a 63-year-old English± Afrikaans-speaking male
who used both languages interchangeably but was more proficient in English
than in Afrikaans. Stuttering was first noted when the subject was six years old,
but he had never received speech therapy. The subject tended to be more aware of
his stuttering in Afrikaans than in English, and evidenced a greater adaptation
effect in Afrikaans than in English but a greater consistency in English than in
Afrikaans. Overall, he was twice as dysfluent in Afrikaans as in English, with
mean dysfluencies per 100 syllables of 14.86 and 7.42, respectively. Moreover,
his dysfluencies were predominantly more typical than atypical in Afrikaans than
in English. The subject was more proficient and stuttered less in his predominant
language, leading the authors to believe that his language proficiency and
dysfluent behavior were interrelated, and that his language ability influenced
the distribution, frequency, and nature of his dysfluencies.
Another case indicating that language proficiency may be a factor in the
origin of a differential stuttering pattern in bilingual stutterers was reported
recently by Scott Trautman and Keller (2000). They studied a 20-year-old male
from Cancun, Mexico whose native language was Spanish but who also spoke
limited English. He had stuttered since age 5 and had never received clinical
intervention. He stuttered in both Spanish and English, approximately 10% in
Spanish, 14% in English. No differences in the nature or distribution of his
dysfluencies were reported.
The likelihood that language proficiency may be an important factor in the
origin of differential stuttering patterns in bilingual stutterers is also supported by
the findings from an experiment with normal speakers by MacKay (see MacKay
& Bowman, 1969). It is well known that delayed auditory feedback produces a
temporary disruption of speech in normal speakers, which is somewhat reminis-
cent of stuttering (Fairbanks, 1955; Lee, 1950). MacKay found that the speech of
bilinguals under delayed auditory feedback is disrupted less when they are
speaking the language with which they are more familiar.

4. Diagnostic considerations

Although speech ±language pathologists have shown considerable interest in

working with bilingual clients in recent years (e.g., see the guidelines of the
194 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

College of Speech and Language Therapists, 1990 and the position papers of
the American Speech ±Language ±Hearing Association, 1985, 1989, 1994), few
specific guidelines for the diagnosis of stuttering in bilinguals are available. An
important diagnostic issue raised by Mattes and Omark (1991) was differ-
entiating stuttering from other types of dysfluency and cited the example of a
7-year-old Hispanic male who was learning English as a second language. In
English, the child's speech was characterized by frequent hesitations and word
repetitions suggestive of stuttering, but these problems were not observed in
Spanish. It appeared, however, that these hesitations and word repetitions
tended to occur whenever the child was having difficulty thinking of the
appropriate English word to use to express his thoughts. Thus, the dysfluencies
observed appeared to reflect the child's limited proficiency in English rather
than a stuttering disorder. Mattes and Omark advised that bilingual children
who are suspected of stuttering should be assessed in both languages.
Assuming that stuttering almost always manifests itself in both languages,
they noted that when dysfluent speech is observed in only one language, it is
likely that it reflects a limited proficiency in that language. They did recognize,
however, that stuttering may be much more apparent in one language than in
the other.
A more extensive framework for assessing a bilingual stutterer was pre-
sented by Watson and Kayser (1994), based on the premises that stuttering is a
unique problem that has been observed across cultures and languages and that
bilingualism is a dynamic, evolving condition that reflects varying levels of
language proficiency. They also pointed out the importance of differentiating
features of stuttering from dysfluencies associated with being a second-
language learner. Like Mattes and Omark (1991), they stressed that distinct
stuttering behaviors must be observed in both languages when identifying a
stuttering problem in a bilingual speaker. If dysfluencies are observed solely in
the second language, they are, according to Watson and Kayser, related to the
acquisition and development of two languages and may be quite different from
the dysfluencies of a stutterer. An additional diagnostic sign of importance
mentioned by Watson and Kayser is the presence or absence of secondary
behaviors. If a bilingual speaker's dysfluencies are not accompanied by
noticeable tension or such behaviors as eye blinks or body movement, then
it is likely that the child is not an incipient stutterer.
There are, of course, other features whose assessment may aid the diagnostic
process. It is generally recognized that stuttering is typically characterized not
only by behavioral characteristics but also by affective and cognitive compo-
nents. Many stutterers develop negative feelings and attitudes about communi-
cation, in general, and stuttering, in particular (Van Riper, 1971). One would not
expect a similar development in reaction to dysfluencies associated with being a
second-language learner. Assessment of the affective and cognitive components,
therefore, may help distinguish a second language dysfluency pattern from
stuttering. Although standardized instruments for assessing feelings and attitudes
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 195

may not be available in some languages, careful listening and recording of

client's statements during an interview can yield much valuable information.
In addition, several studies have reported (see Bloodstein, 1995 for an
overview) that developmental stutterers very often have (i.e., one-third to two-
thirds of cases) a family history of stuttering. Therefore, the presence of a positive
family history of stuttering in a dysfluent bilingual child increases the likelihood
that the child may be stuttering.
As pointed out by Finn and Cordes (1997) identification of stuttering in a
bilingual speaker may be particularly difficult if the second language spoken is
one with which the clinician is not familiar or if the clinician is not similarly
bilingual. For instance, confusion may arise when the unfamiliar language uses
reduplication as a morphophonemic marker, as in some Native American
languages. The clinician may mistakenly perceive such reduplications as instances
of stuttering. Irrespective of whether or not such linguistic reduplication is
involved, it is not known if or how well clinicians are able to make reliable or
valid judgements about the presence of stuttering in languages or dialects other
than their own. One strategy suggested by Finn and Cordes that may help in
identifying stuttering in an unfamiliar language, is for the clinician to compare his
or her judgement with the client's self-judgements. One can, for instance, ask the
client to provide a nonverbal signal (e.g., raising a hand) whenever he or she
stutters. In addition, the use of fluency-inducing conditions (e.g., rhythmic
stimulation, reduced speech rate, delayed or masked auditory feedback, frequency
altered feedback) may help to differentiate stuttered from nonstuttered speech.
Another possible strategy for monolingual speech ±language pathologists is to
call upon a native speaker when assessing a bilingual stutterer, as has been
recommended by Taylor (1986), and Watson and Kayser (1994). Not only can
native speakers help in determining normal fluency parameters of the language
that the speech ±language pathologist is not familiar with, they can also assist in
assessing the client's environment, communication skills, and significant atti-
tudes. Finding native speakers who can function as reliable observers may be
difficult, however. Finn and Cordes (1997) stressed that untrained, inexperienced
interpreters may not provide useful or dependable information about stuttered
speech. English-language investigations (Cordes & Ingham, 1994; Young, 1984)
have found, for example, that untrained, inexperienced judges display unaccept-
able low levels of interjudge and intrajudge reliability for stuttering judgements.
On the other hand, the use of native speakers as informants may be highly
instructive and in many cases the best solution available.

5. Therapeutic considerations

Just as there are no specific guidelines for the diagnosis of stuttering in

bilingual speakers, there are no standard therapeutic approaches either. An often
heard advice for alleviating or eliminating stuttering (e.g., Biesalski, 1978;
196 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

Eisenson, 1986; Rustin, Botterill, & Kelman, 1996) is to temporarily reduce the
number of linguistic systems to which a bilingually raised stuttering child is
exposed. As Rustin et al. (1996) pointed out, it is, of course, important that the
family understands the rationale for such an action and that the language chosen
as the primary language is the one most commonly used by all members of the
household. Evidence from Karniol (1992), who documented the development of
stuttering in a Hebrew ± English-speaking child, suggested that interrupting a
child's bilingual education may indeed prove helpful. The child described by
Karniol started to stutter in his first language (Hebrew), as well as in his second
language (English) at age 25 months, approximately 1 month after the child's
awareness of bilingualism was evident. Within 4 weeks, stuttering became so
severe that the child could barely produce a single utterance in either language
without a stutter, and the parents decided to stop addressing their child in English.
Consequently, the child's use of English was reduced drastically, but stuttering
dropped out entirely at the same time. When the child started speaking English
again, about 6 months after stuttering had stopped, he occasionally evidenced
only minor dysfluencies in both languages.
On the basis of her data, Karniol (1992) concluded that Eisenson (1986) was
correct when he suggested that a child not be exposed to a second language until
he or she has acquired good control of the first language. Not everyone agrees,
however, with this recommendation. For example, Stahl and Totten (1995)
believe that it should not be assumed that counseling bilingual families to limit
themselves to one language is desirable or effective in preventing chronic
stuttering. They suggest that only for particular subgroups of bilingual children
who are at-risk for chronic stuttering, such as those children with first and second
degree family histories of stuttering, or those with speech and language delays in
their dominant language, would temporarily eliminating bilingualism be a
reasonable action. It is impossible to document if deferring a bilingual education
prevents a child from chronic stuttering. Moreover, many families' circumstances
are complex and providing a child with only monolingual experience may not be
an option. For example, when parents speak different mother tongues and have
poor command of each others' language, choosing a single language for
interaction with their children may be very difficult and impractical. When
temporary monolingual education is not possible, Rustin et al. (1996) advise that
each person with whom the child communicates should use a consistent language
so that the child can identify and predict the language he or she is likely to hear.
This advice is based on the principle of ``one person one language,'' which is also
called Grammont's principle after the French phonetician Maurice Grammont
(1866 ±1946) who first formulated it, and is frequently adhered to in bilingual
education in general.
Temporary elimination of bilingualism is clearly not a necessary prerequisite
to successfully reduce dysfluency in all bilingual stutterers, as the bilingual
English ± French-speaking preschooler described by Shenker et al. (1998) illus-
trated. The impracticality of providing a monolingual education led the authors to
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 197

initiate indirect treatment of this child's stuttering while maintaining bilingualism.

Treatment was started 6 months postonset at age 2;11 years when the child was
showing multiple iteration repetitions, tense onsets, and audible and inaudible
prolongations. Therapy was conducted only in English, the child's predominant
language, and consisted first of training parents to model slower turn taking to
reduce interruptions, reductions of linguistic complexity, and rate reductions
through frequent pausing. The parents were encouraged to pursue bilingualism at
home but not to mix languages. The father spoke English to the child, the mother
French. After 4 months, the child's frequency of dysfluency remained over 10%
in both English and French, and a more direct operant approach was initiated,
guided by the work of Onslow (1996). Therapy continued solely in English until
stutter-like dysfluencies decreased to 3% or less when French was initiated for
half of each session. The child's frequency of stutter-like dysfluencies in French,
then decreased to 5.5%. A comparison of the number of iterations per stutter-like
dysfluency at the onset of therapy with those at the end showed that both the
number and severity of the child's stutter-like dysfluencies had decreased in both
English and French.
A noteworthy aspect of the approach of Shenker et al. (1998) is that therapy
was initially conducted exclusively in the child's predominant language (Eng-
lish). Therapy in the second language (French) was initiated only after the
number of dysfluencies had significantly decreased in the child's predominant
language. A similar phased approach was adopted by Scott Trautman and Keller
(2000) in treating a 20-year-old Spanish ± English bilingual male who stuttered.
They, too, started intervention in the subject's predominant language (Spanish)
and introduced treatment in the second language (English) only after target
behaviors had reached a criterion in the predominant language. In both studies,
therapy in the predominant language continued after introduction of therapy in
the second language. Why the investigators started therapy in the predominant
language, is not really clear. Shenker et al. commented that they chose English for
initial treatment because the child produced more complex sentences in English
than in French. Similarly, Scott Trautman and Keller noted that they chose
Spanish for the new target behaviors because their subject ``experienced greater
fluency in Spanish and had better language proficiency in Spanish.'' Neither is it
clear why the investigators in these two studies opted initially to provide
monolingual treatment. Although this approach resulted in a significant increase
in fluency in both languages in both cases, one may wonder if bilingual
intervention from the start might have reduced therapy time. Alternatively, one
could question if bilingual treatment was necessary and if there might not have
been an automatic transfer of the targeted fluency behaviors to the nontreated
language. As Scott Trautman and Keller pointed out, there is a critical need for
studies to compare bilingual to monolingual intervention for such cases.
Data from a study by Druce, Debney, and Byrt (1997) suggest that therapy
outcomes of bilingual stutterers are neither worse nor better than those of
monolingual speakers. Their study was designed to investigate the short- and
198 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

long-term effects of an intensive, behaviorally oriented treatment program for

6- to 8-year-old children who stutter. Six of the fifteen subjects involved were
bilingual. The languages spoken by these children in addition to English were
Slovenian, German, Greek, Hindi, and Italian. All had started bilingual
education during the first 5 years of life and all understood and spoke English
well. Whether or not these bilingual children stuttered in both languages and if
so, showed the same pattern of stuttering in both was not mentioned. However,
treatment and measures of treatment outcome were apparently confined to
English. At any rate, comparisons of the six bilingual and nine monolingual
English speaking children in terms of percentage of syllables stuttered in a 2-
min sample of conversational speech showed no significant difference between
the two groups and no significant association between bilingualism and
outcome. This confirmed the results of a similar investigation (Debney &
Druce, 1988) of children, aged 8 ± 15 years, in which no link was found
between bilingualism and long-term treatment outcome.
Treatment outcomes of bilingual stutterers has also been reported to be less
favorable than those of monolingual stutterers, however. Waheed-Khan (1998), at
the Hospital for Sick Children in Toronto, Canada, found that bilingual children
seen in the treatment program of that Hospital were far less successful in
achieving fluency and in consistently self-correcting their dysfluencies in con-
versation than were monolingual English-speaking children. In addition, the
average number of therapy sessions attended and completion of homework
assignments was lower among bilingual speakers than English speakers. It was
only when a specialized therapy program was developed for bilingual speakers
did the success rate increase and approach that of monolingual speakers. A key
component of this specialized therapy program was the mandatory participation
of a family member who functioned as a ``speech helper.'' This individual
attended therapy sessions, learned fluency targets, reviewed lessons with the
child, modeled target-assisted speech in conversations at home, provided the
clinician with appropriate stimulus materials, and assisted the clinician in
developing homework exercises. As this study illustrates, incorporation of a
client's family in the fluency therapy may be essential for treatment to be
successful for some children.

6. The bicultural stutterer

A final important consideration pertaining to both assessment and treatment is

that bilingual stutterers are often bicultural as well. Clinicians need to be aware of
the possibility that cultural differences may affect the diagnostic and therapeutic
processes. Several examples of cultural factors that may influence clinical contacts
with bilingual stutterers were discussed by Leith (1986). For instance, some
cultures have a different orientation to time so that scheduling diagnostic and
therapeutic sessions may be a problem; the diagnostic interview may be hampered
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 199

if the father always functions as the spokesperson for the family in the family's
culture so that direct questioning of the mother is not possible or if family matters
are private and not to be shared with strangers in the client's culture; therapy may
suffer if the family's culture does not allow a female child to be alone with a male
stranger or if females do not assume an authority's role, such as that of a clinician,
in the client's culture. Clinicians should also keep in mind that maintaining eye
contact is a sign of aggressive, or even hostile behavior in some cultures; that
children are not allowed to initiate a conversation with an adult in some cultures;
and that a child's stuttering is considered a religious punishment for something the
parents have done which can be removed only if the parents atone for their sins in
some cultures. Finn and Cordes (1997) and Leith have provided a number of
recommendations for incorporating the cultural background of bilingual clients
who stutter in their assessment and treatment. They also stress, however, as did
Shames (1989), that empirical data concerning the interactions between cultures
and stuttering are lacking and that much remains to be learned.

7. Fluency out of bilingualism?

As discussed above, bilingualism may be a contributing factor to the develop-

ment of stuttering, and a number of authors (Biesalski, 1978; Eisenson, 1986;
Karniol, 1992; Rustin et al., 1996) have suggested deferring bilingual experience
in order to prevent stuttering. Remarkably enough, just the opposite, initiating
experience to another language to overcome stuttering, has also been recom-
mended. Jean Marc Itard, a 19th century French physician, sometimes advised
that stuttering children be placed in the care of a foreign governess who would
compel the use of a foreign language (Eldridge, 1968). Similarly, BoÈhme (1981)
suggested that bilingualism can be used as a therapeutic factor in the treatment of
cluttering. Indeed, it has been observed that children often do not stutter or stutter
less, at least initially, when they learn a foreign language (Seeman, 1974). A
neurolinguistic explanation for this finding offered by Lebrun (1997) hypothe-
sizes that the extrapyramidal system takes part in speech production under the
control of the cortex under normal circumstances and takes care of the more
routinized or less deliberate aspects of speech, such as articulation and rate of
speech. However, when a speaker uses a foreign language that he has not fully
mastered, he probably has to rely mostly, if not exclusively, on the cortex. Under
these circumstances, extrapyramidal intervention is minimal because few if any
routines have been created. He further hypothesized that cortical control over
extrapyramidal participation in speech production is inadequate in developmental
stutterers. However, when a stutterer uses a foreign language for which he or she
has only a limited command, he or she is not likely to stutter in that language,
because he or she can rely almost exclusively on the cortex. It is only when a
good command of the foreign language is achieved eventually through practice
and exercise that stuttering is likely to manifest itself in that language. A number
200 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205

of routines have then come about, thus, increasing the part played by the
extrapyramidal system. According to this theory, speaking a foreign language
would be comparable to other techniques that require an unusual way of speaking
and that can induce fluency such as syllable-timed speech, singing, whispering,
and speaking in a sing-song way. Perhaps future brain studies of stutterers may
provide evidence supporting this theory.

8. Conclusions

The major conclusions from this review can be summarized as follows. There is
some suggestion that stuttering is more prevalent in bilinguals than in mono-
linguals, but recent studies that corroborate this suggestion are lacking. Prelimi-
nary results of an Internet survey (Au-Yeung et al., 2000) showed nearly identical
percentages of stutterers in monolingual and bilingual speakers, but this study is
methodologically weak. It is likely that bilingualism is a contributing factor to the
development of stuttering, at least in some cases, but other factors such as being
placed in a new situation or exposure to mixed linguistic input may play a role as
well. Why early bilinguals seem to be more prone to develop stuttering and the
extent to which the similarity of the languages learned plays a role is not clear at
present. Stuttering can affect one or both languages of bilinguals. When stuttering
occurs in both languages, they may be equally affected. However, the dominant
pattern seems to be that one language is affected more than the other. Various
factors may determine which language is more affected including language ability
and psychosocial and cultural factors, while linguistic factors may influence the
distribution of dysfluencies in a language. An important diagnostic consideration
is distinguishing stuttering from dysfluencies due to limited proficiency in a
language. Signs that support a diagnosis of stuttering include: dysfluencies occur
in both languages; an individual demonstrates secondary behavior and/or negative
feelings and attitudes about communication; and a family history of stuttering.
Indirect therapeutic approaches for bilingual children who are developing stutter-
ing may temporarily eliminate one language, or if this is not feasible, apply the
principle of one person, one language. Whether or not deferring bilingualism
prevents stuttering is uncertain. There is also a need for studies that compare
monolingual to bilingual intervention outcomes. Therapy outcomes of bilingual
stutterers may be, but not necessarily, less favorable than those of monolingual
stutterers. The assistance of a native speaker of a language that the clinician has
not mastered is advisable for both diagnostic and for therapeutic purposes. Finally,
clinicians should remain aware of the possibility that cultural differences can affect
diagnostic and therapeutic procedures and results. Here, too much information is
needed, and until that information is available clinicians will have to rely on their
professional judgement.
The relationship between bilingualism and stuttering has been called enig-
matic (Karniol, 1992). As the present review revealed, there is a disparity in the
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 201

findings reported in studies of bilingual stutterers, even with respect to such

essential aspects as the prevalence of stuttering, its manifestations and therapy
outcomes. This calls for further research in this area. Perhaps some of the
divergence in studies findings is a reflection of the heterogeneity of the
population under study. In developing future studies of bilingualism and stutter-
ing, investigators should take into account that both stutterers and bilinguals are
heterogeneous populations. No two bilinguals are alike, and as Haugen (1953)
viewed it, the only common thing about bilinguals is that they are not mono-
lingual. This heterogeneity must also be reckoned with by clinicians in their
evaluation and treatment of bilingual stutterers.

Acknowledgments

We are grateful to Nan Bernstein Ratner, Patrick Finn, and an anonymous

reviewer for their interesting and helpful comments on an earlier version of
this paper.

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CONTINUING EDUCATION

Stuttering and bilingualism: A review

QUESTIONS

1. Most of the available data suggest that stuttering

(a) is as prevalent among monolinguals than among bilingual speakers
(b) is more prevalent among monolinguals than among bilingual speakers
(c) never occurs in bilingual speakers
(d) has a prevalence of 50% in bilingual speakers
(e) is more prevalent among bilinguals than among monolingual speakers
2. The available data suggest that
(a) children who are exposed to more than language form birth onward are
not vulnerable to stuttering
(b) only children who are exposed to more than one language from birth
onward are vulnerable to stuttering
(c) younger children especially are vulnerable to stuttering if they are
exposed to two languages
(d) only children who are exposed to more than two languages are
vulnerable to stuttering
(e) adult second language learners especially are vulnerable to stuttering

3. If a bilingual speaker stutters

(a) it is common that he/she stutters in both languages
(b) he/she always stutters in both languages
(c) he/she never stutters in both languages
 J. Van Borsel et al. / Journal of Fluency Disorders 26 (2001) 179±205 205

(d) he/she always shows a similar speaking pattern in both languages

(e) he/she never shows a similar speaking pattern in both languages
4. A temporary elimination of bilingualism in a stuttering child
(a) is not helpful to reduce dysfluency
(b) is a necessary prerequisite to successfully reduce dysfluency
(c) may reduce fluency
(d) is sometimes called ``Grammont's principle''
(e) will prevent a child from chronic stuttering

5. The available data suggest that in bilingual children

(a) only monolingual treatment has a favorable outcome
(b) only bilingual treatment has a favorable outcome
(c) therapy outcomes may be affected by cultural factors
(d) therapy outcomes are better than those of monolingual children
(e) therapy outcomes are worse than those of monolingual children