This revolutionary text approaches the essential topic of second language acquisition in a new way. It differs from more general studies of language in that it focuses on the special challenges of adult language learners, which differ markedly from the challenges of learning first or 'native' languages on virtually all relevant variables. In addition, studies taking an evolutional approach have been limited to the history of language, neurolinguistics, and first language acquisition. In this book, at last, bilingualism and adult second language acquisition are fully investigated from the evolutionary perspective. Ideal for graduate courses in Linguistics, Education, and TESOL, Second Language Acquisition takes an interdisciplinary, research-based approach to explain particular facts about second language acquisition from an evolutionary linguistics and psychology perspective. Five chapters address the scientific foundations of the study of language, how languages develop in the individual, how languages develop in the species, the role of evolutionary linguistics, and a how languages are taught (L2 methodology).