A Vernacular

1. The language of a people or a national language.
2. Everyday speech or dialect, including colloquialisms, as opposed to standard, literary, liturgical, or scientific idiom.
3. Language unique to a particular group of people; jargon, argot.
4. A language lacking standardization or a written form.
5. Indigenous spoken language, as distinct from a literary or liturgical language such as Ecclesiastical Latin.

Synonyms

• (language unique to a group): dialect, idiom, argot, jargon, slang
• (language of a people): vulgate

Antonyms

• (national language): lingua franca, link language, vehicular language