Phonological development in toddlers with Down syndrome and mixed-etiology developmental delays

Consonant inventory and syllable complexity measures were taken at two points from 50 children with developmental delays. Twenty-six children had Down syndrome (DS). Canonical and noncanonical words and utterances, and the initial- and final-consonant inventory were coded during two 15-minute videotaped conversational samples with a parent at two points in time, 18 months apart. For all measures at Time 1 (age ~25 months), the children with DS performed equally well or better than their peers without DS. The reverse was true for all measures at Time 2 (~ 43 months). Phonological skills in young children with DS are delayed beyond the level predictable by mental age during early lexical development. A clear relationship between slow phonological growth and slow lexical growth at the period of "first word" acquisition was established for children with DS