For example, a sociolinguist might determine through study of social attitudes that a particular vernacular would not be considered appropriate language use in a business or professional setting. Sociolinguists might also study the grammar, phonetics, vocabulary, and other aspects of this sociolect much as dialectologists would study the same for a regional dialect.
The study of language variation is concerned with social constraints determining language in its contextual environment. Code-switching is the term given to the use of different varieties of language in different social situations.
William Labov is often regarded as the founder of the study of sociolinguistics. He is especially noted for introducing the quantitative analysis of language variation and change, making the sociology of language into a scientific discipline.