That's a bit minor, don't you think? Frankly, I could barely see the difference between your version and his at first...
Maybe he was simply avoiding the overuse of "the ancient language", so he simply said "the language". Anyways, it's a small thing...
And stop saying he stole stuff, he was inspired by it to a very large extent, he did not simply copy and paste it. Besides, it is a first book (and series) and I can only expect whatever is next to be better.
Eragon is no literary genius, but it is definitly not scum of the editing world either.
Frankly, I don't see how anyone can "hate" a book, you simply don't enjoy it, maybe think it wasn't worth the hype. Or maybe that's just me. I can't hate books, I might just think they're not as good as others.
Then again, remember Eragon was aimed at a certain age, probably young teenagers and the like (which is probably where it got its fame anyway), so you can't expect it to live up to adult/older teen books, especially those from extraordinary authors with years of experience...
So again, it's a series that digs into overused content and manages to tunr it into something different in a classic setting that manages to entertain certain people.