The French
Seriously. The whole language is a mess. They pluralize things with an s at the end, but the s isn't necessarily pronounced, so you can only tell whether someone means one cow or several by the context. Lame. And who was in charge of the French orthography? A word that's pronounced more or less like boojwazee is spelled bourgeosie---ridiculous. Granted, the French do say my name in the sexiest possible way (leading, in high school, to a brief infatuation with a French exchange student), but that's about the only advantage the language has, that I know of. The French word for and, moreover, is the same as in Latin---et. But the Romans used to (as far as anyone knows, anyway) pronounce it exactly how it looks---et. The French, on the other hand, pronounce it ay. Because for some reason t's (t-s) at the ends of words sare quite different from their identical twins that occur elsewhere in a word. Poop on that.
Now, French is, admittedly, a beautiful language to listen to, but it's a terrible language for the average English-speaking person to read. Possibly the French would have the same complaint about English, but we English speakers can call them "frogs" dismissively and ignore that.
Oh well, at least it's not as bad as the transliteration of Asian languages---you'd think that those should correspond to their pronunciations, as we English speakers can basically make them up. But no, somehow we lost our way, and have people in this country who spell their names like Nguyen and Xhiqiang (the latter an actual example of a UCR post-doc). Poop on that, as well.
Addendum: There's an actress out there named Aunjanue Ellis (whom I've seen in The Practice---she was Eugene's ex-wife in a few episodes). Clearly her parents just couldn't spell ingenue, and decided to spell it phonetically. It looks a little odd, but hey, it's obvious how to pronounce it!