With every speech act all individuals perform, to a greater or less extent, an 'act of identity', revealing through their personal use of language their sense of social and ethnic solidarity or difference. At the same time people also have powerful (if unconscious) stereotypes about the norms and standards of their own language and those of others - often at variance with observable behaviour. The view of language use proposed here derives from the authors' extensive fieldwork in the Creole-speaking Caribbean and among West Indian communities in London, and is forcefully illustrated by the data they present, which include recorded conversations and stories. The authors re-examine such concepts as 'a language', 'correct usage', 'race' and 'ethnic groups' and clearly reveal the complex role of language in establishing relationships within regional and social communities and at the state or national level.