Language acquisition is a contentious field of research occupied by cognitive and developmental psychologists, linguists, philosophers, and biologists. Perhaps the key component to understanding how language is mastered is explaining word acquisition. At twelve months, an infant learns new words slowly and laboriously but at twenty months he or she acquires an average of ten new words per day. How can we explain this phenomenal change? A theory of word acquisition will not only deepen our understanding of the nature of language but will provide real insight into the workings of the developing mind. In the latest entry in Oxford’s Counterpoints series, Roberta Golinkoff and Kathryn Hirsh-Pasek will present competing word acquisition theories that have emerged in the past decade. Each theory will be presented by the pioneering researcher. Contributors will include Lois Bloom of Columbia University, Linda Smith of Indiana University, Amanda Woodward of the University if Chicago, Nameera Akhtar of the University of California, Santa Cruz and Michael Tomasello of the Max Planck Institute. The editors will provide introductory and summary chapters to help assess each theoretical model. Roberta Golinkoff has been the director of The Infant Language Project at the University of Delaware since 1974. For the past decade she has collaborated with Kathryn Hirsh-Pasek of Temple University to solve the question of language acquisition in children.