2003 IFA Congress: Montreal, Canada

Examining Adaptation and Bilingualism in Stuttering

Nancy E . Hall1 and David L. Evans2
1University of Maine, 5724 Dunn Hall, Orono, ME, 04469, USA
2Private Practice, Los Angeles, CA, USA


This paper presents the results of an exploratory case study examining the oral-motor rehearsal theory of adaptation by investigating the phenomenon in bilingual people who stu:ter. Through the use of a unique methodology, speakers were asked to read the same passage in one language five times, after which the passage remained the same, but the language changed. This method held linguistic meaning constant, while changing the oral-motor movements. The results are discussed relative to future research efforts.

  1. Introduction
The adaptation effect refers to the reduction in stuttering frequency over successive oral readings of the same material and it generally reaches a plateau -following the fifth reading (e.g., Fierman, 1955; Johnson & Knott, 1939). Studies have explored how the manipulation of the testing situation and the reading material can alter the amount of adaptation and stuttering that occurs (e.g. Dixon, 1955; Max et al., 1997; Porter, 1939). A theory has been developed suggesting that the rehearsal of the oral-motor plan during successive readings contributes to the adaptation effect (e.g., Bloodstein, 1972). According to this theory, the rehearsal of the material allows for greater coordination among the oral articulators, respiration, and phonation.

Literature concerning stuttering among bilingual populations has collectively shown that stuttering often occurs in both languages, greater adaptation is seen in the less proficient language, and speakers may exhibit a higher frequency of stuttering in one language over another (e.g., Jankelowitz & Bortz, 1996).

Examination of the oral-motor rehearsal theory has investigated changes in acoustical parameters of speech withou: regard for linguistic factors. Investigating linguistic factors and their interaction with oral-motor movements during adaptation may shed light on the complexities of the underlying processes involved in speech and language production in stuttering. A way of teasing out these interactions is to isolate certain linguistic variables and hold them constant while manipulating ora.-motor variables. A unique investigative method is to have bilingual individuals who stutter perform adaptation tasks during which the linguistic meaning of the passage is held constant, but the oral-motor movements change as a result of changing the language. This is done by using the same written passage for all readings, but changing the language of the passage half-way through the task. This paper describes the effects of such manipulations on adaptation in two bilingual participants who stutter.

  1. Method
Participants were two bilingual adults who met the following criteria:

  • 18 years of age or older
  • first language was not English 364 Theory, research and therapy in fluency disorders
  • demonstrated developmental stuttering
  • demonstrated stuttering while reading aloud
  • demonstrated a decrease of at least five stuttered moments from Reading 1 to Reading 5
  • reported no history of hearing, neurologic, or communication disorders other than stuttering
  • spoke and read at least two languages proficiently (proficiency defined as a score of 90% or better on a cloze procedure for English [Taylor, 1953]", reported use of each language in both spoken and written form at least once a month, and self-disclosure of proficiency in native language)
A background questionnaire addressing the individuals’ bilingualism, stuttering, hearing, and other history was completed for each participant. The cloze procedure required the participants to provide missing letters throughout a paragraph with 30 partially completed words. The Stuttering Severity Instrument for Children and Adults (Riley, 1994) determined the presence and severity of stuttering in English, and confirmed stuttering during reading. The two participants in the case studies included a female proficient in Polish and English (Participant 1) and a male proficient in French and English (Participant 2). It should be noted that while each participant met the study’s criteria for proficiency in each language, their self-reflections on proficiency suggested differing levels of comfort with the two languages. Both participants indicated greater comfort with English, which was not the native language for either participant.


Two reading passages with comparable linguistic complexity and length (“The Spider’s Home” and “The Toothbrush”) were translated into English and each participant’s native language (L1). Two adaptation tasks were completed: one with Passage A starting in one language, then switching to the other language after five readings; then after a 30-minute break, a second set was completed with Passage B in which the languages were switched. Table 1 presents an illustration of these procedures for the two participants.


Table 1. Reading Sets

No information was given to the participants about the nature or procedures of the study. At the end of each reading, the examiner presented the participant with the same passage on a new sheet of paper and asked the participant to read the passage again.

All readings were audio- and videotape recorded in a quiet room, with only the participant and examiner present. Frequency counts of stuttering from all readings were performed using both the audio- and videotaped recordings following procedures described by Peters and Guitar (1991). Percentages of adaptation were computed for Readings 1 through 5, 1 through 6, 6 through 10, and 1 through 10 for each reading set. The following formula was used to calculate percentage of adaptation: (A-B)/A X 100, where A equals the number of occurrences of stuttering in a prior reading and B equals the number of occurrences of stuttering in any subsequent reading (Ham, 1986). Intra-judge (the second author) and inter-judge (between the second author and a communication sciences and disorders graduate student enrolled in a fluency disorders course) reliabilities for stuttering identification, calculated using Sander’s (1961) Agreement Index were .97 and .92, respectively.

  1. Results
The results for the two case studies are presented in relation to the percentage of adaptation

across the reading tasks. Tables 2 through 5, and Figures 2 and 3 present the individual participant’s data.


Table 2. Adaptation Percentages, Participant 1


Figure 1. Participant 1: Percentage of Stuttered Words Under Two Reading Sets and Two Languages (Set 1, dashed line, English to L1; Set 2, solid line, L1 to English)


Table 3. Adaptation Percentages, Participant 2


Figure 2. Participant 2: Percentage of Stuttered Words Under Two Reading Sets and Two Languages (Set 1, dashed line, English to L1; Set 2, solid line, L1 to English)


Table 4. Participant]: Factor Change from Reading 5 to 6


Table 5. Participant 2: Factor Change from Reading 5 to 6

  1. Discussion
This exploratory investigation provides case study data and a new methodology for examining the oral-motor rehearsal theory of the adaptation effect and may provide research directions in stuttering among bilingual populations. The results on the individual participants indicated differences in stuttering and adaptation among languages and readings. While an adaptation effect was observed for both participants, the conditions in which this effect was observed differed between the two. Participant 1 demonstrated a dramatic increase in stuttering on Reading 6 in a language in which she was less Comfortable and as a result, possible less proficient (Polish); whereas, Participant 2 demonstrated a dramatic increase in Stuttering on Reading 6 in a language in which he may have had greater proficiency because of greater comfor: with that language (English). These findings indicate that language proficiency may or may not have played a role in the observed increased stuttering at Reading 6. Contrasting findings between the participants regarding the role of language proficiency and the role of the oral-motor plan support a speculation that an interaction may exist between language proficiency and oral-motor planning, which then contributes to adaptation; however, the nature of this interaction may manifest differently in individual bilingual speakers who stutter.

Bilingual people who stutter often present as a very heterogeneous population, thus limiting the ability to draw conclusions from data reported in the literature. In light of this, future research should place great importance on obtaining a thorough history of stuttering and language use, and consider possible interactive effects between stuttering and the language spoken. For example, future research should consider: a) differences that may exist between consecutive and sequential bilinguals, b) the possible influential role of culture and a participant’s history of stuttering within a culture or language, and c) differences that may exist between individuals who are bilingual and individuals who are multilingual. In examining these variables in subgroups of bilingual people who stutter, insight may be gained on how these variables affect performance in clinical tasks.

Bloodstein, O. (1972). The anticipatory struggle hypothesis: Implications of research on the variability of stuttering. Journal of Speech and Hearing Research, 15, 487-499.

Dixon, C. C. (1955). Stuttering adaptation in relation to assigned level of anxiety. In W. Johnson & R. R. Leutenegger (Eds.), Stuttering in Children and Adults (pp. 232-236). Minneapolis: University of Minnesota Press.

Fierman, E. Y. (1955). The role of Cues in stuttering adaptation. In W. Johnson & R. R. Leutenegger (Eds.), Stuttering in Children and Adults (pp. 256-263). Minneapolis: University of Minnesota Press.

Ham, R. (1986). Techniques of stuttering therapy. Englewood Cliffs, NJ: Prentice-Hall, Inc.

Jankelowitz, D. L. & Bortz, M. A. (1996). The interaction of bilingualism and stuttering in an adult. Journal of Communication Disorders, 29, 223-234.

Johnson, W. & Knott, J. R. (1937). Studies in the psychology of stuttering: I. The distribution of moments of stuttering in the successive readings of the same material. Journal of Speech Disorders, 2, 17-19.

Max, L., Caruso, A. J ., & Vandevenne, A. (1997). Decreased stuttering frequency during repeated readings: A motor learning perspective. Journal of Fluency Disorders, 22, 17-33.

Peters, T. J. & Guitar, B. (1991). Stuttering: An integrated approach to its nature and treatment. Baltimore, MD: Williams & Wilkins.

Porter, H. V. K. (1939). Studies in the psychology of stuttering: XIV. Stuttering phenomena in relation to size and personnel of audience. Journal of Speech Disorders, 4, 323-333.

Riley, G. D. (1994). Stuttering severity instrument for children and adults (3â_˜d ed.). Austin, TX: Pro-ed. 368 Theory, research and therapy in fluency disorders

Sander, E. K. (1961). Reliability of the Iowa speech disfluency test. Journal of Speech and Hearing Disorders, Monograph Supplement, 7, 21-30. Taylor, W. L. (1953). “Cloze procedures”: A new tool for measuring readability. Journalism Quarterly, 30, 415-433.

The research reported here represents a portion of the Master’s thesis work conducted at the University of Maine by the second author under the direction of the first author.
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