VoiceOver

VoiceOver is a screen reader built into Apple Inc.'s Mac OS X, iOS and iPod operating systems. By using VoiceOver, the user can access their Macintosh or iOS device based on spoken descriptions and, in the case of the Mac, the keyboard. The feature is designed to increase accessibility for blind and low-vision users, as well as for users with dyslexia.

Read more about VoiceOver:  Mac OS X, IPod Shuffle, IOS, IPod Nano