Even seasoned andhra singers over the years have been happy with singing two or three stock tamizh songs in their TN concerts--songs with lots of sanskritized words too? Malladi Brothers are singing more of late, I'm glad to observe (based on my reading the lists and listening to them, MK).The Rudrapatnam school has a few tamizh songs that they sing in tamizh nADu. To sing in AP is a cinch for all, thanks to T! Then there are those who speak tamizh, live in TN but barely include tamizh krutis in their concerts in Chennai or elsewhere ;(
What about malayalam? There is a great number of CM rasikAs in kerala. I would be surprised if I hear that a non-malayalam speaking vidvAn sang in malayalam there. Agreed, TMK did, in his Margazhi M Utsavam concert

Short of breaking out into a manipravalam song, how much of singing in the local language is done by non-keralite performers?
Coming back to tamizh songs, I also want to say that things are slowly changing. I am listening to more tamizh songs now and yes, bArati songs too.
I am surprised to see many requests for contemporary tamizh songs in our own Sahitya Section these days. It so happens that several of them are requests for what Sanjay has been singing in recent years. I find that other performers sing more tamizh songs too.
Not only that, you may hear them on youtube by our vocalists (mainly from MMUtsavam). Sanjay has put up other tamizh songs and viruttams in his blog now--from his London concert and several others. Nice of him to share his music with rasikas. My guess is that he realizes that his livelihood is not going to be affected by sharing a bit of his music with others. Is it some kind of self-promotion, someone asked. CM singers like Sanjay, TMK and Vijay Siva don't 'need' any self-promotion. They have reached the point of recognition where such a thing is unnecessary. All that they have to do is keep the quality of their singing intact, enjoy singing, teach what they know to talented students AND sing a lot of tamizh songs. Though I consider myself a citizen of the world, I'm first and foremost, a tamizhmagaL, after all!