In the preceding chapter, we focused on variation in language use found in different geographical areas. However, not everyone in a single geographical area speaks in the same way in every situation. We recognize that certain uses of language, such as the slang in Kate Burridge's description, are more likely to be used by some individuals in society and not by others. We are also aware of the fact that people who live in the same region, but who differ in terms of education and economic status, often speak in quite different ways. Indeed, these differences may be used, implicitly or explicitly, as indications of membership in different social groups or speech communities. A speech community is a group of people who share a set of norms and expectations regarding the use of language. The study of the linguistic features that have social relevance for participants in those speech communities is called ‘sociolinguistics’.