[1][2] 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.
[3] The term sociolect might refer to socially restricted dialects,[4] but it is sometimes also treated as equivalent with the concept of register,[5] or used as a synonym for jargon and slang.
A sociolect is distinct from a regional dialect (regiolect) because social class, rather than geographical subdivision, substantiates the unique linguistic features.
"[9]: 122 This idea of a sociolect began with the commencement of dialectology, the study of different dialects in relation to society, which has been established in countries such as England for many years, but only recently has the field garnered more attention.
[10]: 26 However, as opposed to a 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.
[9]: 35 Asif Agha expands the concept by stating that "the case where the demographic dimension marked by speech are matters of geographic provenance alone, such as speaker's birth locale, extended residence and the like".
An example of a sociolect difference, based on social grouping, is the zero copula in African American Vernacular English.
[9]: 23 Diglossia, associated with the American linguist Charles A. Ferguson, which describes a sociolinguistic situation such as those that obtain in Arabic-speaking countries and in German-speaking Switzerland.
[9]: 107 Register is "a language variety that is associated with a particular topic, subject, or activity...." Usually, it is defined by vocabulary, but has grammatical features as well.
For example, Halliday states that "in areas with Diglossia, the link between language and success is apparent as the higher, classical register is learned through formal education".
Furthermore, referring back to the diglossia expressed in the Arab-speaking world and the Tamil caste system in India, which words are used must be appropriate to not only the social class of the speaker, but the situation, the topic, and the need for courtesy.