nonstandard
non·stand·ard [non-stan-derd]
–adjective
2. not conforming in pronunciation, grammar, vocabulary, etc., to the usage characteristic of and considered acceptable by most educated native speakers; lacking in social prestige or regionally or socially limited in use: a nonstandard dialect; nonstandard English. Compare standard (def. 27). (1)
the idea that language has a ‘standard’ is a vitally important one. it [...]