Phonology and grammatical morphology in specific language impairment: Accounting for individual variation in English and Italian

Abstract

ABSTRACTChildren with specific language impairment (SLI) often show more limited use of grammatical morphology than younger, normally developing children matched according to mean length of utterance (MLU). However, within groups of children with SLI, individual differences are seen in grammatical morpheme use. In this study, we examined the role of weak syllable use in explaining some of these differences. Employing two different languages – English and Italian - children with SLI were placed into pairs. The children in each pair showed similar MLUs; however, one member of the pair showed a greater use of particular function words. In each of the pairs examined in both languages, the children with the greater use of function words also showed a greater use of weak syllables that did not immediately follow strong syllables. The weak syllable productions of children showing a more limited use of function words in each pair seemed to be dependent on a strong syllable-weak syllable production sequence. This sequence appeared to be operative across several prosodic levels, as defined within the framework of prosodic phonology. Because weak syllables that follow strong syllables usually have longer durations than those that precede strong syllables, the findings might have a perceptual basis. However, the results raise the possibility that limitations in prosody can restrict the degree of grammatical morpheme use by children with SLI.