While I was breaking my brain to find the binary data of that file I had a very interesting idea: since we can get practically all the strings from that file without even knowing its structure, we could make a tool or a program to translate all of them into the language that we desire.
As far as I know, in that file there's practically everything: npc dialogs, system messages, quest descriptions/help, system/GUI strings... So a lot of people would be able to enjoy the game in their own language.
And it doesn't look like the file's going to be corrupted if we change strings :P
So what I'm unable to do there is to write a program that encodes the file back to what the TERA client will read. Is that possible for you without having to spend so much time?
Thanks a lot!