Re-translation of a unity game

Apr 14, 2022
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Recently I've been playing some old japanese games, and one thing I've noticed is that the old mtl on unity is not very good, like in octo massage.
I want to ask if there's a way to somehow go into the game's code, that the speach strings and change it manually. I also don't know if this is ok from a ethical standpoint. do I have to have the game creator permission or something?