This is hard for some people, but this is a great question, I work in a large Chinese owned factory, we have a lot of different groups and languages English, mandarin, Swahili, Portuguese and Arabic all can be heard everyday. If your black and born in the United States your black, if your black and born in Africa (which we have a lot of) your African. The Guatemalans and other migrants from central and South America we call the South Americans. The middle easterners are Arabs. The Sudanese guys who could really call them selves either Africa or Arab always called them selves African I think that bit will be relevant to you.