Performance interactions and developmental asynchrony in the language of children with and without SLI

This study investigated level of development and performance interactions between the three language domains of semantics, syntax, and morphology across and within two groups of children. Eight children with normal-language (NL), ranging in age from two to four, and eight children with SLI, ranging in age from four to six, served as subjects. For all subjects, individual language samples were collected, analysed, and coded for semantic, syntactic, and morphological characteristics. The unit of analysis for all language measures was the communication unit. For the level of development question, it was found that in comparison to a language-matched group of normally developing children, the children with SLI evidenced lower levels of development in morphology, but not in syntax and semantics. Furthermore, for both the SLI and NL children, developmental levels were only modestly correlated among the three linguistic domains. For the performance question, it was found that the morphological performance of the SLI children was reduced as a function of syntactic complexity; the same was not true for the language-matched NL children. Furthermore, the semantic elaboration of both groups of children was reduced as a function of syntactic complexity. The data were interpreted as supporting both asynchronous development, across the three language domains for both groups, and on-line processing trade-offs between the three domains, for the SLI group.Medicine, Faculty ofAudiology and Speech Sciences, School ofGraduat