That bad English is such a cruel take. It made me think, most people know of Cockney rhyming slang, but it's origin is prison rhyming slang, the prisoners didn't want to be understood except by fellow prisoners. Taking that example, and this is only my conjecture, a slave arriving in a foreign land, afraid and knowing that brutality awaits everywhere. Why wouldn't they do what the prisoners did in Victorian England? Strikes me as a most sensible way of avoiding the slave master's whip.