This grant provides support for an NIH Autism Center of Excellence (ACE). Disorders of communication are core deficits in autism. Children with autism spectrum disorders (ASD) not only have problems with expressive language, they also show deficits in understanding as well as early failures to orient to speech and name. This project aims to examine precursors of these deficits by investigating auditory preferences known to be present in typically developing infants and to support the growth of social engagement and language. The study will follow ASD, developmentally delayed (DD), and typically developing (TD) infants from the time that they are 12-24 months old until they are 36-48 months old. It will test the hypothesis that infants with ASD will show reduced preference, relative to DD and TD peers, for listening to speech under controlled social conditions and for speech with maternal inflections (as opposed to neutral intonations). Listening preferences at an early age (12-24 months) may be predictive of the children that will meet ASD diagnostic criteria when diagnosis is confirmed at 36-48 months.