The Mac has always been able to read stuff on the screen out loud. But Apple has taken this feature light-years farther, turning it into a full-blown screen reader for the benefit of people who can't see. Voice Over doesn't just read every scrap of text it finds
on the screen—it also lets you control everything on the screen (menus, buttons, and so on) without ever needing the mouse.
As you can guess, learning VoiceOver means learning a lot of new keyboard shortcuts (see the massive table at the end of this section). Fortunately, most of them involve the same two modifier keys pressed together: Control-Option.
VoiceOver works beautifully in Cocoa programs like Safari, TextEdit, and Mail, but doesn't work well in iTunes, Microsoft Word, ...