The standard native language of a country or locality.
The everyday language spoken by a people as distinguished from the literary language.
A variety of such everyday language specific to a social group or region: the vernaculars of New York City.
The idiom of a particular trade or profession: in the legal vernacular.
An idiomatic word, phrase, or expression.
The common, nonscientific name of a plant or animal.
An example of "southern" vernacular:
"I'm fixing to do that." Meaning, "I am going to do that, without a doubt. But not yet."
The common, often local, general dialect.
Or, even more general,
What is spoken.
"Every word or phrase in [urban dictionary] should be part of your vernacular."
Commonly Heard after accidental rhymes or verbose expression:
"Excellent usage (of the vernacular)."
Vernacular is referred to by Truly in Chitty-Chitty Bang-Bang
The style of language used by those on George Washington University's Mount Vernon Campus. This form of language is usually recognized by its archaic word choice, its back-woods stylistic formation, and its anti-social, primitive, exclusionary leanings. Most often used by those who are sympathetic to the [vern supremacy] cause.
Did you hear Regina's vern-acular? That commoner has clearly not been associating with anyone for month.
When Maynard started using words and phrases like 'golly gee,' 'slick as a pig,' and 'poppycock,' we knew he had started using vern-acular.