The way we talk is deeply influenced by our class, sex and ethnic background. It can also have a profound effect on how we are perceived by others. In this fully updated new edition of a classic text, Peter Trudgill explores the evidence - and the huge implications for social and educational policy. Why do men swear more than women? How do speech styles of most Black Americans, and whites growing up in "Black areas" differ from those of other whites? Does it makes sense to defend a language against "contamination" from foreign words and phrases? Why are languages dying out at a catastrophic rate and what can we do about it? Should Serbo-Croat now be called Serbian, Croatian or even Bosnian? And in what sense, if any, is standard French "better" than Quebecois or High German "better" than Schweizerdeutsch? Such questions illuminate many fascinating aspects of human communication, but they also lie at the heart of fierce political debates about how states should deal with their linguistic minorities, when teachers should correct their pupils' grammar and pronunciation, and whether language promotes racial and sexual stereotypes. Only socio-linguistics can provide objective answers: their key conclusions are set out in this celebrated book.