Mac OS X 10.4: Computer speaks unexpectedly, or a black box unexpectedly appears around a file, folder, or other item
If a black outline (or box) unexpectedly appears around a file, folder, icon, button, or other item when you click it, VoiceOver is probably enabled. Your computer might also be unexpectedly speaking items that you click on.
If you don't want VoiceOver on, turn it off in the Universal Access preference pane, or by pressing Command-F5 (or Fn-Command-F5 if you have an iBook or PowerBook).
Tip: If you want to prevent the Command-F5 key combination from turning VoiceOver on or off, go to Keyboard & Mouse preferences, click the Keyboard Shortcuts tab, then deselect the "Turn VoiceOver on or off" shortcut.