Green’s Dictionary of Slang

biatch n.

also beatch, bee-ach, beeatch, bee-otch, beeyatch, beitch, bia, byotch
[deliberately exaggerated pron.]

[1980s+] (US black/teen) a var. of bitch n.1 ; can be used to refer to a male or a female, a friend or an enemy, as an excl. etc.