Spanish is the easiest on our tongues, I swear. With Spanish, what you see is exactly how you pronounce it.
I used to wanted to learn French and Latin, but the pronunciation is killing me, I can't deal with that.
I have a quirk for modern science-y books. I also get interested on something mostly based on who the creators are.
So when John Green finally published his first non-fiction book, I had to get my hands on it as soon as possible.