Speech perception and language acquisition in the first year of life.

During the first year of life, infants pass important milestones in language development. We review some of the experimental evidence concerning these milestones in the domains of speech perception, phonological development, word learning, morphosyntactic acquisition, and bilingualism, emphasizing their interactions. We discuss them in the context of their biological underpinnings, introducing the most recent advances not only in language development, but also in neighboring areas such as genetics and the comparative research on animal communication systems. We argue for a theory of language acquisition that integrates behavioral, cognitive, neural, and evolutionary considerations and proposes to unify previously opposing theoretical stances, such as statistical learning, rule-based nativist accounts, and perceptual learning theories.