Vernacular

Belonging to the country of one's birth; one's own by birth or nature; native; indigenous; -- now used chiefly of language; as, English is our vernacular language.

The vernacular language; one's mother tongue; often, the common forms of expression in a particular locality.

being or characteristic of or appropriate to everyday language; "common parlance"; "a vernacular term"; "vernacular speakers"; "the vulgar tongue of the masses"; "the technical and vulgar names for an animal species"