Review of Studies on Syntactic Development in Children and Adults with Intellectual and Developmental Disorders:

Abstract

It is known that people with intellectual and developmental disorders (IDD) have more deficits in syntactic than other linguistic abilities. However, only a few studies on the syntactic development of people with IDD have been conducted in Japan. As a result, basic studies, accumulated data and the development of assessment methods have been deficient in Japan compared to other countries. This review compared international research findings with studies conducted in Japan. The results indicated that various factors affect the acquisition of syntactic knowledge, including the type of disability and the educational environment, which have not been sufficiently investigated. Based on the results, we have discussed the need to conduct future studies in Japan. It is suggested that future studies need to undertake the following tasks. (1) Developing scales for assessing language development to objectively and comprehensively evaluate syntactic development. (2) Investigating factors affecting syntactic development in people with IDD from perspectives other than the mental age (MA) and intelligence quotient (IQ), including the type of disability, life experience, and cognitive development, among others. (3) Investigate syntactic development in IDD people based on their stage of development, i.e., before or after acquiring grammar.

Syntactic development in children with intellectual disabilities – using structured assessment of syntax

“…However, previous studies on syntactic development in Japanese children with ID indicate that effective methods of support and evaluation have not been developed in Japan to date (Koizumi and Kojima 2019). A delay in syntax development in children with ID might be affected by the level of intellectual development and also by traits of disabilities and individual differences.…”

Morphosyntactic abilities in young children with Down syndrome: Evidence from the Greek language

“…It is only when these children begin attending school at approximately the age of 6 that they begin to make their first word combinations, forming smaller sentences compared with their peers (Iverson et al., 2003). Therefore, their academic performance is usually poor, as school demands for expressive language increase and students with Down syndrome are unable to adequately meet them (Koizumi & Kojima, 2019; Yirmiya et al., 1998). Studies that examined oral retelling and discussion in both children and adults with Down syndrome claim that their expressive syntactic skills are impaired.…”