Language acquisition is a contentious field of research occupied by cognitive and developmental psychologist‎,‎ 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 Huniversity of 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.‎