In sociolinguistics, a sociolect or social dialect is a variety of language (a register) associated with a social group such as a socioeconomic class, an ethnic group (precisely termed ethnolect), an age group, etc.
Sociolects involve both passive acquisition of particular communicative practices through association with a local community, as well as active learning and choice among speech or writing forms to demonstrate identification with particular groups.
Individuals who study sociolects are called sociolinguists. Sociolinguists study language variation. Sociolinguists define a sociolect by examining the social distribution of specific linguistic terms. For example, a sociolinguist would examine the use of the second person pronoun "you" for its use within the population. If one distinct social group used 'yous' as the plural form of the pronoun then this could indicate the existence of a sociolect. A sociolect is distinct from a dialect because social class rather than geographical subdivision substantiates the unique linguistic features.
A sociolect, defined by Peter Trudgill, a leading sociolinguist and philosopher, is "a variety or lect which is thought of as being related to its speakers' social background rather than geographical background". This idea of sociolect began with the commencement of dialectology, the study of different dialects in relation to social society, which has been established in countries such as England for many years, but only recently has the field garnered more attention. However, as opposed to dialect, the basic concept of a sociolect is that a person speaks in accordance with their social group whether it is with regard to one's ethnicity, age, gender, etc. As William Labov once said, "the sociolinguistic view…is that we are programmed to learn to speak in ways that fit the general pattern of our communities". Therefore, what we are surrounded with in unison with our environment determines how we speak; hence, our actions and associations.
The main distinction between a sociolect and a dialect, which are continually confused, is the settings in which it is created. A dialect's main identifier is geography: a certain region uses specific phonological, morphosyntactic or lexical rules. Asif Agha expands the concept by stating that "the case where the demographic dimension marked by speech are matters of geographic provenance along, such as speaker's birth locale, extended residence and the like". However, a sociolect's main identifier is socioeconomic class, age, gender, and ethnicity in a certain speech community.