This groundbreaking new study takes a novel approach to reduplication, a phenomenon whereby languages use repetition to create new words. Sharon Inkelas and Cheryl Zoll argue that the driving force in reduplication is identity at the morphosyntactic, not the phonological level, and present a new model of reduplication - Morphological Doubling Theory - that derives the full range of reduplication patterns. This approach shifts the focus away from the relatively small number of cases of phonological overapplication and underapplication, which have played a major role in earlier studies, to the larger class of cases where base and reduplicant diverge phonologically. The authors conclude by arguing for a theoretical shift in phonology, which entails more attention to word structure. As well as presenting the authors’ pioneering work, this book also provides a much-needed overview of reduplication, the study of which has become one of the most contentious in modern phonological theory.