(δια and λέγω, to speak); the form or idiom of a language peculiar to a particular province, state, or kingdom. The ancient Greek language possessed four dialects, the Attic, Ionic, Æolic, and Doric.

In Great Britain, besides the grand diversity of English and Scotch, almost every county has a dialect of its own, all differing considerably in pronunciation, accent, and tone, although one and the same language.