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Nonverbal communication and early language acquisition in children with Down syndrome and in normally developing children.

Many children with Down syndrome display asynchrony in development with the acquisition of language preceding at a slower pace than the acquisition of other cognitive skills. Recent research suggests that the expressive language delays that are displayed by these children may be associated with an earlier disturbance in the development of nonverbal requesting skills (Mundy, Sigman, Kasari, & Yirmiya, 1988; Smith & von Tetzchner, 1986). To test this hypothesis, a longitudinal study of 37 children with Down syndrome and 25 children with normal development was conducted. The results of the study indicated that this sample of children with Down syndrome exhibited a disturbance in nonverbal requesting. Furthermore, individual differences in nonverbal requesting were associated with the subsequent development of expressive language in these children. This association was observed even after taking into account initial variance in developmental level and language status. These data suggested that some of the processes involved in the expressive language delay of children with Down syndrome were not unique to linguistic development. Instead, some aspects of this delay appeared to be associated with problems in an earlier nonverbal phase of communication development. Additionally, the results suggested that measures of nonverbal communication skills also made a unique contribution to the prediction of language development among children with normal development. These data supported the hypothesis that the acquisition of nonverbal communication skills provides an important foundation for the emergence of language in atypical as well as typical development.