From - http://xbox.joystiq.com/By: Griffin McElroy
As far as we can tell, there are two types of people who care about whether the North American version of Final Fantasy XIII has a Japanese voice track (in addition to an English one) -- RPG-loving hipsters who strive for complete, unwavering authenticity in everything they say and do, and ... well, people who speak Japanese and live in America, we suppose. Unfortunately for both these groups, it seems the Japanese voice track might only appear in the PS3 version of the highly anticipated Squeenidos title.
In a recent Q&A with IGN, FFXIII producer Yoshinori Kitase explained that without the kind of memory available on Blu-ray, there's simply not enough room on the 360 to implement two vocal tracks. He added, "Are there many people who would like to play with Japanese voices?" Well, gang? Are there?