FFXIII and FFXIII-2 already have this option. I hope this will be available for the following parts as well.
I didn't notice that in XIII. Is is just options?
For this option you need the Asian version of the game.
Like
this. *check the language option at the bottom of the cover.
Just select the English language in PS3 system settings, and the game starts with the Japanese voices and English subtitles.
As an additional bonus, this version supports the saved data from U.S. or European versions.
So you can continue to play from any location where you stopped

Unfortunately this version of the
FFXIII has long been sold out.
But the second part is
still available 