Lexical knowledge and lexical use in autism.

One aspect of autistic language that has been infrequently researched is vocabulary and the conceptual knowledge underpinning individual words or word types. In this descriptive study we investigate anomalous vocabulary use in a 70,000-word corpus of conversational autistic language and examine evidence that concept formation, and hence vocabulary, is abnormal in autism. Particular attention is paid to the expression of artifact and temporal concepts which some believe may develop abnormally in autism.