informal vs vernacular

informal is not a noun while vernacular is a noun.

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

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

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