There's a website answering your question, I don't remember exactly what it was but it was through the CIA I think.
They need:
Arabic
Pashto
Urdu
Farsi
French (good for if you're doing missions in Africa)
Korean
Chinese (Mandarin, Cantonese)
Maybe Russian too....not sure.
They need people...
Ooooh yes...very obvious.
The only way it wouldn't be obvious was if you didn't really have an accent, which could take a while to develop if you aren't someone who can pick it up easily.