WindowsXP has a built in voice. Look in the control panel under Speech. Sounds like the old miggy... but then most software speech synthesizers do unless you use sampled sounds from different people.
I looked at building a new narrator.device when Commodore stopped including one but at that time the Amiga was too slow to run the code. I looked at porting what I had done to AROS a few years ago and with no sound or sound standard it wasn't worth messing with at the time. I supposed I should dig out the code again and give it a go.