In a case where they share the same content, is running the Japanese version of a game always faster than the NTSC/PAL version? Is the reason only because of text density? If not, then what are other things to consider?

the majority of games are faster in japanese, in some games you could have J version exclusive glitches.

i personally like to run J games more mainly because of competition.

It varies game by game, and is mainly because of text speed. In a game with a lot of dialogue and not much voice acting then the fewer characters you see, generally the faster the game is in those sections.

Games of Japanese origin (Ones that are released in Japan first, then exported) will often be different to the international versions of the game because of the extra time they have during the translation process to work on the lesser bugs they didn't have time to fix.

Cool, thanks y'all

Not all games are faster on Japanese. I'm pretty sure Superstar Saga is faster on English.

Majority =/= all games haha

Just a few games I know on top of my head:

Crash 1 (any%) is faster on NTSC-U than J, even though levels are easier and one of them is much shorter on J. Reason being the animation at the end of a level, which you can skip on U with death abuse, but can't on J. Ironically, J is faster for 100%. Resident Evil 3: China version is the best PogChamp Yeah, China version. Not J, not U, not w.e, it's freaking China. Digimon World 4: The text shows up all at once on both J and U, so there's no difference at all.

So while J is usually faster, that's not always the case.

@Deln I didn't see your first post, just relying to OP :P

While there are a lot of games that use japanese for faster text, this is not always the case. As pretty much with every speedrun everything can vary. They may also be running on japanese because a certain glitch may have only been patched in the english version. Maybe they only own a japanese console. (Like how I only have a JP PS2). It really just comes down to the specific game.