Referential communication skills of children with Williams syndrome: understanding when messages are not adequate.

Although children with Williams syndrome have relatively good structural language and concrete vocabulary abilities, they have difficulty with pragmatic aspects of language. To investigate the impact of pragmatic difficulties on listener-role referential communication, we administered a picture placement task designed to measure ability to verbalize message inadequacy to a speaker separated by a barrier. Participants were 57 children with Williams syndrome 6 to 12 years of age. When messages were inadequate, children verbalized that a problem was encountered less than half the time. The likelihood that children would indicate a message was insufficient and that children who verbalized message inadequacy also would effectively communicate the problem varied as a function of type of problem encountered, theory of mind knowledge, receptive vocabulary, and CA.