Sociolinguistics is the study of the effect of any and all aspects of society, including cultural norms, expectations, and context, on the way language is used.
It also studies how lects differ between groups separated by certain social variables , e.g., ethnicity, religion, economic status , level of education, etc., and how creation and adherence to these rules is used to categorize individuals in social class or socio-economic classes. As the usage of a language varies from place to place (dialect), language usage varies among social classes, and it is these sociolects that sociolinguistics studies.
For example, a sociolinguist might determine through study of social attitudes that Black English Vernacular would not be considered appropriate language use in a business or professional setting; he or she might also study the grammar, phonetics, vocabulary, and other aspects of this sociolect much as a dialectologist 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.
Sociolinguistics differs from sociology of language in that the focus of sociolinguistics is the effect of the society on the language, while the latter's focus is on the language's effect on the society.
Studies in the field of sociolinguistics typically take a sample population and interview them, assessing the realisation of certain sociolinguistic variables. Labov specifies the ideal sociolinguistic variable to
- be high in frequency,
- have a certain immunity from conscious suppression,
- be an integral part of larger structures, and
- be easily quantified on a linear scale.
Phonetic variables tend to meet these criteria and are often used, as are grammatical variables and, more rarely, lexical variables. Examples for phonetic variables are: the frequency of the Glottal stop, the height or backness of a Vowel or the realisation of word-endings. An example for grammatical variables is the frequency of Double negative.
The Language War, Robin Tolmach Lakoff, University of California Press, Berkeley, California, 2000, hardcover, 322 pages, ISBN 0-520-21666-0