Apple has built in a screen reader. Normally when you buy a PC, you will purchase or use an open-source screen reader that's made by a separate company. What Apple has done is they've put people on the development of screen readers within Apple. It's built right into the Mac or the iPhone or the iPad. When you turn on this screen reader, you have access to all of the applications that come with the iPad and many third party applications that you would download from the App Store. One of them is the iBookstore. You can do things like read by sentence, or by word, or by character, which is essential if you want to spell a name or take a bit more fine-grained reading approach.
So that's what Apple has done. They've built the screen reader directly into the product, and anyone can turn it on or off, as they wish.