A dialect peculiar to the illiterate classes; a provincial form of speech.

a characteristic language of a particular group (as among thieves); "they don't speak our lingo"

a regional dialect of a language (especially French); usually considered substandard

A regional dialect. Several dialects of American English could be considered examples; the distinctive New Orleans dialect is a patois.

Local dialect; often linked with colloquial language of Jamaica.

Patois, although without a formal definition in linguistics, can be used to describe a language considered as nonstandard. Depending upon the instance, it can refer to pidgins, creoles, dialects, and other forms of native or local speech, but is not commonly applied to jargon or slang, which are vocabulary-based forms of cant. Class distinctions are embedded in the term, drawn between those who speak patois and those who speak the standard or dominant language used in literature and newscasts—the "acrolect" in professional jargon.