I have noticed in several places now that some people are confused about what’s “VoiceOver” and what’s “Text to Speech” in terms of Mac OS X. This post is to attempt to clarify what each one is and why it’s important to know which one you’re talking about if you’re asking for help.
“Text to Speech” is any time your computer is converting typed words into spoken ones. If you highlight a paragraph in TextEdit and then use control-click -> Speech -> Start Speaking to get the computer to talk to you, that’s text to speech. If you use the services menu with the Speech -> Start Speaking Text command to do it, that’s text to speech too. If you use a program like GhostReader or iSpeak It to convert text into a spoken file to listen to on your iPod, that’s using text to speech too.
“VoiceOver” is a special use of text to speech to allow blind and vision impaired people to use a Mac OS X computer without seeing the screen. Here’s Apple’s description of VoiceOver:
…an accessibility interface that gives you magnification options, keyboard control and spoken English descriptions of what’s happening on screen. If you have a visual impairment, VoiceOver enables you to work collaboratively with other Mac users or work on their computers without assistance.
There’s a demo of VoiceOver and more information on the Apple accessibility website.
In other words, if it speaks but it doesn’t let you use the computer with your eyes closed it’s not VoiceOver!