you would benefit from a little research on the history of the Omani arabs in Kenya. Arab-muslim (rulers and slave traders) intermarried with the indigenous peoples, and as the female line doesn't count in islam, there are no lack of blacks in Kenya who claim arab descent - just as there are black arab muslims living in Oman itself. Most are descendants of black slaves but they identify themselves as arabs through the male line, none-the-less.
It's difficult for me to understand why you included the matter of laguage in your comment. obama learned the koran by rote whilst in school in Indonesia. The koran is written in an archaic arabic that even arabic speaking peoples do not fully understand.
Please explain why this is relevant. (I'm not discounting the possibility that some tenuous Arab connection may be a matter of great significance to the Luo.)