During an interview, FFXIII producer Yoshinori Kitase has said the team are "thinking" about including only the English voice work and not any Japanese.
There'd be "enough memory" with Blu-ray on PS3, but the Xbox 360 "probably not" due to disc space limitations. It's vague but the PS3 version outside of Japan could contain both.
"Obviously, when we talk about XIII it's for PS3 and Xbox," said Kitase-san in IGN's Q&A, "with PS3 being on Blu-ray there would be enough memory, but on Xbox probably not.
At the same moment we're thinking of releasing the voice in English only. Are there many people who would like to play with Japanese voices?"
Those looking to brush up on their Japanese Final Fantasy style may have cause for concern, but hey, the franchise is coming to Xbox 360 - what more do you leeches want?
You never know, perhaps we'll get 'Engrish' instead? 
