APA Dictionary of Psychology

n. the situation in which two varieties of a language coexist and have distinct social functions within a community; these are usually characterized by high (H) and low (L) uses, H being associated with formality and literacy, and L with everyday colloquial usage. See also code switching; multilingualism; vernacular. [first described in 1959 by U.S. linguist Charles Ferguson (1921–1998)]