Wow, thanks for your reply.
About 2). Confirmed. I've just used eng instead of "English" and spa instead of "Spanish; Castilian" within #original_language and it perfectly works.
But with this situation, it would be really nice if you could add a new possible "Languages"-type column in the "Add your own columns" section. I mean from a plain user point of view, it's quite odd storing eng, spa, or whatever other needed code.