SociolinguisticsSociolinguistics 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 dialects differ between groups separated by certain social variables, e.g., ethnicity, religion, economic status, level of education, etc. Creation and adherance to these rules is a useful way to categorize individuals in social class or socio-economic classes. William Labov is often regarded as the founder of the study of sociolinguistics.
For example, Black English Vernacular or Pidgin languages would not be considered appropriate language use in a business or professional setting, whereas, sociolinguistically speaking, the former are both considered acceptable variations on the base language.
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.
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.