A thoroughly updated edition of this prize-winning, readable introduction to the main theories of first and second language acquisition. This book introduces you to some of the language acquisition research that will help you not just to evaluate existing materials, but also to adapt and use them in a way that fits what we currently understand about how languages are learned. — Content including new research and new areas in pedagogy to provide an up-to-date and comprehensive overview of research in the field. — Chapter Preview s and Summaries with round-up questions. — Companion website with vodcasts, content updates, and shared user content. — Also available as an e-book.