"We've never needed to know foreign songs ourselves, people seem to bring them with them" That's the great thing about folk music!

A couple thoughts--

There are a lot of music sites on line, and many places that you can find MP3's of different kinds of music from the cultures that you are interested in--thing is that it is hard to figure out what is what--it helps to know someone who knows the music--

There is a Middle Eastern tendency for musicians to be seriously schooled in traditional music, and if you ask around, you'll often find people who know the music really well and are polished musicians. For reasons that we know only to well, musicians and performers tend to be political exiles as well, and there are a few names whose repertoire has great emotional meaning--for a lot of Iranians, this person is the singer, Googoosh--

Nother thing is to figure out when the religious festivals are and how they are celebrated in the communities you are looking at--These a very good time to get to know people and make musical connections--if there are musicians, this is when they'll appear(plus there will be lots of good food)--