PHONOLOGY AND GRAMMATICAL MORPHOLOGY IN SPECIFIC LANGUAGE IMPAIRMENT - ACCOUNTING FOR INDIVIDUAL VARIATION IN ENGLISH AND ITALIAN

Children with specific language impairment (SLI) often show more limit ed use of grammatical morphology than younger, normally developing chi ldren matched according to mean length of utterance (MLU). However, wi thin groups of children with SLI, individual differences are seen in g rammatical morpheme use. In this study, we examined the role of weak s yllable use in explaining some of these differences. Employing two dif ferent languages - English and Italian - children with SLI were placed into pairs. The children in each pair showed similar MLUs; however, o ne member of the pair showed a greater use of particular function word s. 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 sy llables that did not immediately follow strong syllables. The weak syl lable productions of children showing a more limited use of function w ords in each pair seemed to be dependent on a strong syllable-weak syl lable production sequence. This sequence appeared to be operative acro ss several prosodic levels, as defined within the framework of prosodi c phonology. Because weak syllables that follow strong syllables usual ly have longer durations than those that precede strong syllables, the findings might have a perceptual basis. However, the results raise th e possibility that limitations in prosody can restrict the degree of g rammatical morpheme use by children with SLI.