Abstract
While there has been increasing interest in language development in children and adolescents with Down's Syndrome, the research in Japan, especially during the last fifteen years, has not been summarized and analyzed concerning deviancies in their language development and communication. Analysis of recent research in the field indicates that the following five points are well supported by the research. 1) While the response of children with Down's syndrome to others is weak, there is no evidence of deviance in their communication during the pre-linguistic period. 2) The prevalence of inconsistent articulation errors is leading researchers to believe that children with Down's syndrome may have neural disorders in areas such as articulation programming and auditory processing. 3) The development of syntax lags behind their MA and MLU, while growth in their lexicon is faster than that of syntax. 4) It seems that various types exist in terms of speech and language development among children and adolescents with Down's syndrome. 5) The use of sign language has been shown to help promote language acquisition.
