The Turkish folksinger Ruhi Su had a career path in some ways like Rhiannon Giddens. He started out with Western opera - he had a powerful baritone voice that should have got him an international career, but he was blacklisted by the Turkish government for being a Communist. Turkish art music was similarly state-regulated, and he seems never to have tried it, or anything related to it (there are popularized classical genres he could have worked in, but didn't).

Instead he went for the traditional bardic ("ozan") folk music most closely associated with the Alevi mystical/Sufi/secularist minority who have been the core of the Turkish left for the last century. He became a superb saz player and got the idiom spot on, though you can always hear the operatic-professional control in his voice. Musically this was a good choice of direction in that the modal system of Turkish folk is more similar to Western folk and art music than it is to the Ottoman art music that says "classical" to the Turks - it's mostly in the Dorian mode with none of the microtonal modulation the art music tradition goes in for.

One thing he didn't try was getting dialect right - he sings everything in the Istanbul dialect you'd hear on the news. (Not sure if Rhiannon Giddens makes much effort in that direction either?) The upshot is that his songs are great learning material for the standard language.