The Koreanic languages is a language family consisting of the modern Korean language together with extinct ancient relatives closer to it than to any proposed links with Mongolic, Turkic, Tungusic, or Japanese. Among extant languages, Korean is considered by most linguists to be a language isolate, and by others as part of the widely rejected Altaic family. The Jeju language of Jeju Island, considered by some as a dialect of modern Korean, is distinct enough to be considered a language in its own right by other authorities. Some consider that rather than being a language isolate, Korean forms a small language family together with Jeju.
Modern Korean is traditionally considered a single language. However, Jeju (Cheju) is sometimes classified as a distinct language, for example in the UNESCO atlas on endangered languages. If that is accepted, there are two modern Koreanic languages, Jeju and Korean proper.