The company that provided the base technology for Say, translator.library, etc. is still around, according to Workbench Nostalgia.
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.
Actually, I believe that is because the very company that provided the text-to-speech libraries on Amiga is who Microsoft subcontracted for the accessability features (narrator, etc) in Windows. I could have sworn I read that somewhere. Of course, I can't find the source, now... :-P