Spanish and then afterwards French. Spanish is probably the most useful language for anyone living in the US to learn, french is very easy to learn if you already know how to speak Spanish. Chinese and Japanese are garbage languages for weeaboos that you'll never actually use. That said it's unlikely you'll use french very often unless you visit Canada (:barf:) or France.
Edit: In the end I doubt you'll attempt learning a foreign language at all, learning a foreign language in school is probably the class most kids hate (Including myself) so I'm almost positive you won't have too much fun teaching your self how to speak one.
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