Code-switching -the alternating use of several languages by bilingual speakers- does not usually indicate lack of competence on the part of the speaker in any of the languages concerned, but results from complex bilingual skills. This volume brings together the main strands of current research in four major areas: the policy implications of code-switching in specific institutional and community settings; the perspective of social theory on code-switching as a form of speech behaviour in particular social contexts; the grammatical analysis of code-switching; and the implications of code-switching in processing and development.