Apple were one for the front runners in TTS technology back in the 80’s and Mac OS was the first to include it out of the box. You would have thought that this would make the Mac the best platform for TTS but for some reason it went on the back burner and wasn’t significantly updated until the latest release of Mac OS with the introduction of the Alex voice.
So Mac OS has always had TTS but you really wouldn’t want to listen to it as the synthesized voices were either comical or just plain annoying. With the release of 10.5 comes Alex, a much more natural sounding American* male TTS engine. While Alex is a great leap forward for us Mac users there still isn’t the ability to control him. It you want a web page or document read back to you then you’ll get the whole thing, no pauses or the ability to rewind you have to stop it and reposition your cursor and start where you left off. Its fine if you do want to have a document read back but most people will want to have some control. Alternatively you can choose a modifier key in the text to speech control panel to speak selected text, this is my preferred option.
This is pretty basic technology these days so there are quite a few options around for reading back text. More useful though if you have problems with spelling, grammar or reading is having words or sentences read back to you as you type. Its like having a proofreader on hand 24 hours a day. Mac OS supports this function in one form via Voice Over but it will also read back navigation commands which for non-VI users could be a distraction. There are a few programs that I know of that provide this functionality and I’ll be looking at them soon.
Verdict: Alex is a massive improvement but if you want anything other than american pronunciations then you'll need to look elsewhere. The lack of control also makes TTS on the Mac a pain.
*You can buy third party voices by Assistiveware and Cepstral which are very good and come in many different languages.
