Abstract
Psychological differences between the two linguistic performance modalities are addressed. Evidence of correct production coexisting with incorrect comprehension in the language repertoires of young children is reviewed. An explanation is presented which links children's linguistic performance with their retrieval mechanisms and underlying cognition. Differences between the two modalities are characterized as intrinsic to the retrieval pathways through a child's fluid mental representation system. In the case of children, there are no sharp distinctions among linguistic comprehension, production, and general knowledge. Instead, all performance and understanding are embedded in a fluctuating, interrelated thought system.