Sociolinguistics is the descriptive study of the effect of any or all aspects of society, including cultural norms, expectations, and context, on the way language is used, and society's effect on language. It can overlap with the sociology of language, which focuses on the effect of language on society. Sociolinguistics overlaps considerably with pragmatics and is closely related to linguistic anthropology.

Sociolinguistics' historical interrelation with anthropology can be observed in studies of how language varieties differ between groups separated by social variables (e.g., ethnicity, religion, status, gender, level of education, age, etc.) and/or geographical barriers (a mountain range, a desert, a river, etc.). Such studies also examine how such differences in usage and differences in beliefs about usage produce and reflect social or socioeconomic classes. As the usage of a language varies from place to place, language usage also varies among social classes, and it is these sociolects that sociolinguistics studies.

Sociolinguistics can be studied in various ways such as interviews with speakers of a language, matched-guise tests, and other observations or studies related to dialects and speaking.