Defining language phenotypes in autism

All children with autism spectrum disorders have deficits in pragmatic aspects of communication; however, formal language abilities are extremely heterogeneous, ranging from nonverbal to superior linguistic skills. Recent studies have focused on defining different language phenotypes among verbal children. One subtype has been compared to specific language impairment (SLI), a language disorder that is diagnosed on the basis of delays and deficits in language acquisition in the absence of hearing impairment, frank neurological damage or co-morbid psychopathology. Two behavioral studies address the question of whether children with autism and language impairment have specific language deficits that are similar to those found in SLI. These experiments focused on phonological processing in a nonsense word repetition task, and use of grammatical morphology in conversational speech. The findings from these studies are discussed in the context of recent neuroimaging and genetic studies of autism.