Syntactic processing in developmental dyslexia and in Specific Language Impairment : a study on the acquisition of the past participle construction in Dutch

Abstract

Most children acquire reading skills relatively easily. However, a small proportion of the population has significant difficulties in learning how to read. These individuals suffer from developmental dyslexia. Currently, dyslexic children are diagnosed only after they have tried (and failed) to acquire reading skills. Ideally, dyslexic children should be identified before the onset of reading instruction. An early diagnosis could lead to early intervention which, in turn, could have a positive effect on dyslexics' reading ability. This ideal has inspired researchers to search for early precursors of dyslexia.

The main goal of this study was to identify linguistic precursors of dyslexia. Since dyslexia is a genetic disorder, a viable way to identify linguistic precursors of dyslexia is to study the language development of children with a genetic risk of developing dyslexia. This dissertation focuses on the morphosyntactic development of children at risk for dyslexia. More precisely, children's mastery of the past participle construction was studied longitudinally. The at-risk children was compared to normally developing children and to children with Specific Language Impairment (SLI).

An important finding of this study is that children with a predisposition for dyslexia differ from normally developing children with regard to their morphosyntactic development. The at-risk children do not exhibit deviant morphosyntactic development, but their representation of specific morphosyntactic dependencies seems vulnerable. In complex sentences, these children are more likely (than normally developing children) to generate ungrammatical constructions, to omit functional items such as auxiliaries and determiners and to omit verbal morphology. The behaviour of the at-risk children is best accounted for by assuming that they suffer from a limited processing capacity that affects their control over morphosyntactic dependency relations.