Prosodic markers of syntactic boundaries in the speech of 4-year-old children with normal and disordered language...

This study focuses on the potential role of prosodic "boundary features" in developmental disorders of morphosyntax. As exemplified melodically by the final portion of the falling tone and rhythmically by final syllable lengthening, boundary features mark the right edge of major constituent units in speech and thus phonetically reflect syntactic structure on the level of clauses and sentences. To resolve conflicting findings about the development of boundary features in children with specific language impairment (SLI), this study describes the falling tone and final syllable lengthening in the spontaneous speech of 10 four-year-old children with the phonologic-syntactic type of SLI and 10 four-year-old children with normal language development. The results--indicating that some prosodic boundary features are normal in preschoolers with SLI--show that impairments of morphology and syntax on the segmental level of the grammar do not implicate systematic deficits in syntax-sensitive features on the suprasegmental level. The potential dissociation between prosodic and morphosyntactic development is shown most clearly by the remarkable robustness of the falling tone, which was observed in 9 of the 10 children with SLI, in spite of the moderate to severe deficits they demonstrated in segmental phonology, morphosyntax, and mean length of utterance.