Language Competence in Populations other than Specific Language Impairment an Introduction

Different populations of children are associated with variability in language competence. Most cases are considered disorders of language—such as the language of children with a variety of neurodevelopmental disorders or children with SLI. Yet, in other cases, the linguistic competence of the child indeed varies from what is most commonly observed yet it is not disordered. Ethnic dialects (e.g., African Americans; see de Villiers, chap. 17 in this volume) are such cases. Interestingly, if Sandler’s view (chap. 15 in this volume) of sign languages is accepted, then sign languages also are an example of nondisordered natural variability in linguistic competence.