From Merriam Webster's :
AIN'T
Etymology: contraction of are not
1 : am not : are not : is not
2 : have not : has not
3 : do not : does not : did not -- used in some varieties of Black English
Usage: Although widely disapproved as nonstandard and more common in the habitual speech of...
ESL Vocabulary and Idioms
by
Mister Micawber
3 yr 340 days ago
American English, Verbs, Grammar, British English, Constructions, Numbers, Pronunciation, Spelling, English Grammar, Contractions, Dialects