Mothers' lexicon of internal state words in speech to children with Down syndrome and to nonhandicapped children at mealtime.

This study examines internal state words in mothers' speech to children with Down syndrome, and the relation between the use of internal state words and the children's levels of social-adaptive, communicative, and linguistic functioning. Results indicate qualitative differences in mothers' use of internal state words to children with children Down syndrome, compared with a sample of maternal speech to nonhandicapped children who were matched on the Vineland scales for their level of adaptive functioning. Differences include use of fewer internal state words overall to children with Down syndrome, and different kinds of internal state words: more words referring to physiological states, and fewer words referring either to affect or to cognition. In general, child Mean Length of Utterance (MLU) was associated with the pattern of inner state words used by mothers, whereas no associations were found between children's social-adaptive competence and maternal input. Even when controlling for child MLU, there were, however, some qualitative differences in the inner state lexicons used to children with Down syndrome. Results suggest that speech to children with Down syndrome that is calibrated to their MLU may underestimate their competence in domains other than grammar.