if the font files are unpacked, then just replace the file with it with your own (in order not to get into the game code, rename your file to the one in the game resources) - they have the .ttf extension. If the game is packed, then unpack it with this program and do the part above. If your game crashed after unpacking (it shouldn't, I tried to translate it and everything worked) - do the same 1 point, then transfer the entire folder with fonts to a clean game