I think it's that I was allowed to use the new shouts they taught me even though I'd only killed two dragons, but before I can learn more, I've got to play catchup. Got 4 souls now, but 5 words, so just keeping an eye out for the next dragon.
Someone mentioned reading the books on your phone rather than the PC - how do you do that? Is there some sort of 'Books of Skyrim' ebook?