If your level of willpower requires you to delete your characters to stop you from playing on an English speaking server then whats to keep you to whatever program you artificially contrive to keep yourself speaking Spanish?

At any rate, the servers probably wont be a super large amount of help in formally learning the language. If its anything like the US server youll be able to pick up a good amount of slang though, which is another skill (maybe) =)

Not to derail, but my wife is looking into getting some of that rosetta stone software... you guys have much luck with it? How is it?