The facts that the Turkish language has been added and the Greek one removed, don't have anything to do with one another.
The Turkish language was added because that one wasn't there before, but someone made it. The Greek language was removed, because it was only half done, many things were not translated.
Related threads:
"Bug" in greek translation,
Greek in Plus! 3,
Greek translation - Volunteer to improve it! and
Greek Translation Finished