Divergence of verbal expression and embodied knowledge: Evidence from speech and gesture in children with specific language impairment

It has been suggested that phonological working memory serves to link speech comprehension to production. We suggest further that impairments in phonological working memory may inuence the way in which children represent and express their knowledge about the world around them. In particular, children with severe phonological working memory deŽcits may have difŽculty retaining stable representations of phonological forms, which results in weak links with meaning representations; however, nonverbal meaning representations might develop appropriately due to input from other modalities (e.g., vision, action). Typically developing children often express emerging knowledge in gesture before they are able to express this knowledge explicitly in their speech. In this study we explore the extent to which children with speciŽc language impairment (SLI) with severe phonological working memory deŽcits express knowledge uniquely in gesture as compared to speech. Using a paradigm in which gesture-speech relationships have been studied extensively, children with SLI and conservation judgement-matched, typically developing controls were asked to solve and explain a set of Piagetian conservation tasks. When gestures accompanied their explanations, the children with SLI expressed information uniquely in gesture more often than did the typically developing children.