Speech fluency in bilinguals who stutter: Language proficiency and attentional demands as mediating factors.

Purpose: The current study examines how speech disfluencies manifest themselves in the two languages of bilingual persons who stutter, starting from the hypothesis that stuttering is associated with an attentional deficit at the level of speech production.

Methods: Twenty-eight bilingual people who stutter performed a spontaneous and a controlled speech production task, once in their dominant and once in their non-dominant language. The controlled production task (i.e. a network description task) was carried out once under a full-attention condition and once under a divided-attention condition where a non-linguistic, pitch discrimination task was performed simultaneously.

Results: In both the spontaneous and the controlled speech task, bilingual persons who stutter produced more (typical and stuttering-like) disfluencies in their L2 than in their L1. Furthermore, whereas the typical disfluencies increased when attention was directed away from speech production, stuttering-like disfluencies decreased. This effect was however restricted to L2. In addition, L2 proficiency was generally found to be a predicting factor, with higher proficiency leading to fewer disfluencies.

Conclusions: These results suggest that speaking in a non-dominant language increases both typical and stuttering-like disfluencies in bilingual persons who stutter, but also that these two types of dysfluencies differ regarding their attentional origins. Our findings offer further support for attentional accounts of stuttering and have both theoretical and clinical implications.