vernacular vs informal

vernacular is a noun but informal is not a noun.

Word	Noun	Adjective	Verb	Adverb
vernacular	Yes	Yes	No	No
informal	No	Yes	No	No

vernacular (noun)	informal (noun)
the everyday speech of the people (as distinguished from literary language)
a characteristic language of a particular group (as among thieves)

vernacular (adjective)	informal (adjective)
being or characteristic of or appropriate to everyday language	not formal
	used of spoken and written language
	having or fostering a warm or friendly and informal atmosphere
	not officially recognized or controlled