This is one of the first systematic attempts to bring language within the neo-Darwinian framework of modern evolutionary theory, without abandoning the vast gains in phonology and syntax achieved by formal linguistics over the past forty years. The contributors, linguists, psychologists, and paleoanthropologists, address such questions as: what is language as a category of behavior; is it an instrument of thought or of communication; what do individuals know when they know a language; what cognitive, perceptual, and motor capacities must they have to speak, hear, and understand a language? For the past two centuries, scientists have tended to see language function as largely concerned with the exchange of practical information. By contrast, this volume takes as its starting point the view of human intelligence as social, and of language as a device for forming alliances, in exploring the origins of the sound patterns and formal structures that characterize language.