I'd say that they could be your average Joe, where a tribe would be an exceptionally large family of sorts who live together, yeah. They speak the same language, have the same house style etc. And I know that you didn't mean they're a different race, but your picture seemed to denote that. :p That guy is barely human at all. 

Like I said, hill-tribes would be a cool thing, and if you would agree to it you can make them akin to hill tribes, except they live in area x, of your creation. Are we cool on that, then?