Alright so first of all, I believe this is the right Board.
Now, I am rather unsure if this is a safe thing to do:
There is a way to change the language(fullly, both text and voices) to Korean. The method is that it is necessarry to download the Korean client from their webpage and after it patches up, you need to change the system.yaml file with a different one(everything is the same as in the original, except that it is changed so it connects to the EUNE server game and client wise).
The reason I want this is that I am currently learning Korean so having the game in Korean is helpful in a certain way and also because the English voices are becoming boring to me along with the game. I know that some of the people from Reddit have already tried this months ago and they have no problems at all. Also, this method is quite similar to the one with getting the Japanese language, but I just want to be 100% sure that one day my account isn't going to be suspended just for playing in a different language.