Effect of Language Proficiency on the Severity of Dysfluency in Bilingual Students Who Stutter

The aim of this study was to examine the effect of language proficiency in the severity of dysfluency in Kurdish-Persian bilingual stutterers. In the analytical study, 31 Kurdish-Persian stuttered students with a mean age of 10 years and nine months were selected using convenience sampling. Language proficiency and the severity of dysfluency in the two languages with regard to indexes of language complexity, lexical diversity and Stuttering-like Dysfluencies Scale, were obtained using analysis of spontaneous speech, and were compared together. Language complexity in Persian, (including Mean Length of Utterances, length of five long sentences, number of verbs in the sentence, and number of dependent clauses in the sentence) were higher than in Kurdish significantly. Also, lexical diversity was higher in Persian than in Kurdish, but the difference was not significant. Participants stuttered in both languages, and the severity of dysfluency was higher in Persian than in Kurdish. The dominant language was Persian, due to incessant and compacted training of the language to students. Lack of teaching the mother tongue to these students at school, had weakened their learning, and brought about unequal conditions for learning both languages. The severity of dysfluency was higher in the dominant language (Persian), due to psychosocial factors (such as the participant's viewpoints on Persian culture and language, and their motivation for learning it). Probably due to the provision of courses in Persian, the participant's negative experiences regarding this language were higher and they had a more severe stuttering in this language for the same reason. A positive emotional relationship with the mother tongue could also be one reason for this condition.