Specific language impairment (SLI) and autism spectrum disorders (ASD) involve primary impairments in language and communication. The basis of the proposal is that neurobehavioral markers of risk in fundamental processing systems (e.g., auditory/speech; visual/social) can be detected in the latter half of the first year of life. In a longitudinal study following infants from 6 to 36 months of age, data will be collected on language and social perception using behavioral, eye-tracking, and neurophysiological measures as well as general measures of cognitive and brain development (head circumference; EEG). The findings from this research will help develop early screening and diagnosis methods to identify infants at high risk for SLI and ASD. In turn, children identified as showing significant risk signs at much younger ages will be able to take advantage of early interventions that may prevent the onset of autism symptoms or reduce the severity of the disorder.