Sociolinguistics is the study of how language serves and is shaped by the social nature of human beings. In its broadest conception, sociolinguistics analyzes the many and diverse ways in which language and society entwine. This vast field of inquiry requires and combines insights from a number of disciplines, including linguistics, sociology, psychology and anthropology.
Sociolinguistics examines the interplay of language and society, with language as the starting point. Variation is the key concept, applied to language itself and to its use. The basic premise of sociolinguistics is that language is variable and changing. As a result, language is not homogeneous not for the individual user and not within or among groups of speakers who use the same language.