Originally published in 1979. This book studies language variation as a part of social practice - how language expresses and helps regulate social relationships of all kinds. Different groups, classes, institutions and situations have their special modes of language and these varieties are not just stylistic reflections of social differences; speaking or writing in a certain manner entails articulating certain social meanings, however implicit. This book focuses on the repressive and falsifying side of linguistic practice but not without recognising the power of language to reveal and communicate. It analyses the language used in a variety of situations, including news reporting, interviews, rules and regulations, even such apparently innocuous language as the rhymes on greetings cards. It argues for a critical linguistics capable of exposing distortion and mystification in language, and introduces some basic tools for a do-it-yourself analysis of language, ideology and control.