Man, are you a language professor, a science professor, or a home ec teacher? Pick one! If you're gonna sound pretentious, stick to one subject at least. You'll make everybody else look bad!

[It is debatable whether Masaomi knows the exact definition of the word "pretentious," but he continues nonetheless.]

But the answer you're looking for is that we've all been dumped into a bad sci-fi tv show. That's why all the aliens look and sound human.