Babies are not born talking, they learn language, starting immediately from birth. How does this process take place? When do children master the skills needed for using language successfully? What stages do they go through as they learn to understand and talk? Do the languages they learn affect the way they think? This new edition of Eve Clark's highly successful textbook focuses on children's acquisition of a first language, the stages of development they go through, and how they use language as they learn. It reports on recent findings in each area covered, includes a completely new chapter on the acquisition of two languages and shows how speech to children differs by social class. Skilfully integrating actual data with coverage of current theories and debates, it is an essential guide to studying language acquisition for those working in linguistics, developmental psychology and cognitive science.