patois (n.)

"a provincial dialect, a dialect peculiar to a district or locality," especially among the uneducated classes, 1640s, from French patois "native or local speech" (13c.), a word of uncertain origin, probably from Old French patoier "handle clumsily, to paw," from pate "a paw," from Vulgar Latin *patta (see patten), in other words, a "clumsy" manner of speaking. Compare French pataud "properly, a young dog with big paws, then an awkwardly built fellow" [Brachet]. Especially in reference to Jamaican English from 1934.