Tschingis Aitmatov

Tschingis Aitmatov (1928-2008) had - like Beckett and Brink - two literary languages. He has written his books in his first language Kirghiz and in Russian. First he wrote in Khirgiz and translated his works into Russian. Later he decided to write them first in Russian so they could get translated faster in other languages, but he still tried to continue self-translation now in the other direction (Russian > Kirghiz):

Unfortunately, the language in which I write is not always my own decision, but is often a matter of circumstance. I often write in Russian now, because it is in my interests to do so; books get published and disseminated faster, and are also translated more quickly into other languages. Time is short, so I take the quickest way. I make a point, though, of at least trying to translate my own work into Kirghiz-though it is not always possible to do so. (Aitmatov, 1990:197)

For further reading:
Aitmatov, Chingiz (1990): Voice from the Republics. An Interview. In: Third World Quarterly 12: 1, p. 194–200.