Aion language

Hi all, i have a friend who's just started to play aion, and he wants to play it in his language (spanish in this case), the european version of the client hast most of the quests and skills trasnlated, is there a way to change the current NA client to another language?. As far as i know there's a file in the L10N that changes the language, but im not sure which file is it, and which files do i need to trasnlate the game, any help will be apreciated
PD: i made him play here so he can have a quick preview of the classes in aion and have a general idea of what the pvp and instance looks like