Word production inconsistency of Singaporean-English-speaking adolescents with Down Syndrome.

Background: The nature of speech disorders in individuals with Down Syndrome (DS) remains controversial despite various explanations put forth in the literature to account for the observed speech profiles. A high level of word production inconsistency in children with DS has led researchers to query whether the inconsistency continues into adolescence, and if the inconsistency stems from inconsistent phonological disorder (IPD) or childhood apraxia of speech (CAS). Of the studies that have been published, most suggest that the speech profile of individuals with DS is delayed, while a few recent studies suggest a combination of delayed and disordered patterns.