A black kid growing up in Hawaii....can’t sound black...end of the story. You end up sounding fake every time you attempt the slang.
accents can be a hoot. my frau has an aunt who was english but has lived in east tennessee for most of her adult life. i picked up a texas accent when i was stationed in germany and, as i am from maryland, i am confused for a southerner in new england (which i am) and a damnyankee in georgia.
i hear it is also funny to hear second generation vietnamese shrimpers on the gulf coast speak with a texas accent. judging folks like that is just sillt. take an adopted chinese 2 month old baby, raise her in america and tell her she is chinese when she is 18 and be prepared to apologize. she is probably more american than half of the folks who have lived here for 3 generations.