Let's face it, over the years there have been some pretty terrible English dubs of Japanese games. Moreover, these horrible dubs often replace an excellent Japanese voice cast. Now while there is nothing wrong with liking your Japanese games in English with English voices, have you ever wished you could just play some of your favorite Japanese games in the original Japanese with English subtitles? Well, you're not the only one.
For years now, various game hackers from across the net have been taking their favorite Japanese games and "undubbing" them. Simply put, after getting the game both in English and in the original Japanese, they replace the English audio files with the audio files extracted from the Japanese version. The result is just what you'd expect: a fully localized version of the game but now with Japanese voices.
Of course, creating an undub is far from easy. To start with, every game is different in design and structure; so switching the audio files is often no easy task. You need to have at least some working knowledge of the game's code to even find the files you want to replace. Moreover, even after the files are swapped, the timing for the voices—i.e., when they start and stop—often no longer syncs up. The only way to fix this is to manually edit the game's code.
Despite these hurdles, more than a few people have released their undubs online for others to download. These undubs cover everything from PS2 games to DS games to Wii games. Big named RPGs like the Final Fantasies, Personas 3 and 4, and various games from the Tales series have all received the undub treatment.
Luckily, as time goes by and disc size increases, more and more games are released with the Japanese voices included in addition to the English ones. But until the day that this is the case with all games, it's a comfort to know that with the right skills, you can undub them.