IGN recently had the chance to talk to Yoshinori Kitase about Final Fantasy XIII, and one of the things discussed was the option to have the Japanese voice work present in the Western versions of the game. This is something that many Western gamers crave, as typically the English voice actors don't capture the essence of the characters as well.

Kitase stated that:

"Obviously, when we talk about XIII it's for PS3 and Xbox - with PS3 being on Blu ray there would be enough memory, but on Xbox probably not. At the moment we're thinking of releasing the voice in English only. Are there many people who would like to play with Japanese voices? "

So, it's still a possibility on the PlayStation 3 due to the Blu-ray disc, but the Xbox 360 version definitely won't be seeing any Japanese voice work.