[AlfredoDore]

today I made a hack (my first) which was Final Fantasy Crystal Chronicles, I changed the audios in English to Japanese in the European PAL version and it worked perfectly, now I'm thinking of replacing the English language with Spanish in Resident Evil 2 Japanese version, for cause the 60Hz code of the PAL version doesn't work, the problem is that I have no idea what language files are in it
could someone clarify me?

[FAST6191]

It is rarely that easy for text - many of the same things you would have to tackle with a straight up translation* you will also have to tackle with backporting a script, especially if the Japanese version was the first version of the game.

Even without that "I have no idea what language files are in it" is kind of the point. If you have Spanish (or English) then the relative search options of something like https://www.romhacking.net/utilities/513/ might give you an idea, and chances are it will be files named similarly/in similar folders/similar extensions/similar overall format.

*font issues (Japanese probably does not have ch, ñ and LL if you are going to roll that way), text included in binary (usually menus or something), encoding issues and space issues perhaps.