Relationship between language and fluency in children with developmental language disorders.

The present investigation addresses two primary hypotheses: (a) that a subset of children with developmental language disorders exhibits significantly more disfluencies than other children with language disorders and (b) that differences between the disfluent and nondisfluent groups observed in fluency may be related to differences in language deficits. Spontaneous language samples from 60 preschool children with developmental language disorders were analyzed for frequency and type of disfluencies. Comparisons of the frequency of disfluencies across subjects revealed that a subset of 10 subjects exhibited significantly more disfluencies than the other subjects with language disorders. Demographic, intelligence, and language variables were compared across the two groups to determine whether such factors could account for the differences in fluency. The subjects with greater percentages of disfluencies were found to be significantly older and demonstrated significantly higher scores on two standard measures of vocabulary. These findings were interpreted in light of two models of disfluencies: the neuropsycholinguistic (Perkins, Kent, & Curlee, 1991) and Demands and Capacities (Adams, 1990; Starkweather, 1987). This suggests that some children with language disorders are at risk for fluency breakdown because of dysynchronies in the development of lexical and syntactic aspects of language or as a result of mismathces between speaking demands and capacities.