I really think it's Indonesian though, because of the inflection in the voices, especially one of the higher pitched ones sounds VERY screachy and similar to the Indonesian monkey chant "kecak" from the movie Baraka, that was also used by Mike Patton and Mr Bungle on the album California - Goodbye Sober Day
Hans Zimmer did a similar type of contest on UJam a month ago for Assassin's Creed Revelations and that was a success so I'm not surprised that he is doing this again. I would like to see how this will turn out.