When I was a kid, everything had a speech synthesizer in it, more or less. A couple years back I started to wonder where the technology is going after all these years, and after some research found that it's going nowhere. Storage has increased, making concatenative synthesis more life-like, but little else has improved.
Text to speech seems to be the primary research field. Most books I've found of the subject of speech synthesis skim on the actual voice generation and then spend hundreds of pages on text to speech.
I'm not interested in text to speech as such, but more on the voice generation. Yet, I haven't found a single book with good, practical explanation of this. Concatenative synthesis is simple to grasp, but formant is the one I'd like more information about. (The third method, physical modelling, would be a plus, but not all that interesting).
What makes this game specific is that I'd love to make a tool that lets low budget/downloadable games have speech, without having to go out to get actual voice actors and having to store hundreds of megs of oggs with the game. Since the author is in complete control of the voice editing before release, text to speech is less important; what's more important is the voice synthesis.
So, anyone know any good books about this?