If you choose the "Language" option in the "Options" menu you should be able to press left and right to choose your language.
If you aren't able to do this, you can edit "GameOptions.sav" and set "language" to the ISO code of your language. (ex: change "language":"en" to "language":"ja")
In either case you may need to exit the "Options" menu or restart the game after making the change.