I'm surprised there isn't like an overlay type program that could work -- kind of like how phones can translate things their camera points at. Rather than having to get the text inside the game, since that's a giant pain in the ass.
From what I could tell... most of it is... semi-random. I have seen this before, but not on an executable. This would take me.... I have no idea, as I would have to go line by line to be certain I did not alter any hidden parameters within the text. Things like this are usually done to prevent 'Unauthorised Translations'.
You cannot just edit the dialogue trees... because they are randomised, with reference tables to make it work in game... from what I saw.