Arabic

Would have been a more popular langauge if half of its consonants weren't so hard for non-arabs to pronounce. Arabic is also one of the few languages where it is compulsory to write in cursive: every American's nightmare. Believe it or not, Arabic is way easier to learn than Japanese, though, at least when it comes to reading and writing. And if you learn Arabic, you'll look way cooler than that classmate who's fluent in Japanese.