The volume includes an examination of the psychological and neurological processes of implicit and explicit learning, what aspects of language learning can be affected by explicit learning, and the effects of bilingualism on the mental processing of language. Rigorous empirical research investigations probe specific aspects of acquiring morphosyntax and phonology, including early input, production, feedback, age, and study abroad. A final section explores the rich insights provided into language processing by bilingualism, including such major areas as aging, third language acquisition, and language separation.