Hi lightspeed,
I use the AT&T with my Sandy, I have the text to speech reader installed, it allows me to change the speed of the voice, but not the pitch.
Mostly because the AT&T voices were not programmed with this ability, the voice has to be programmed with the ability to change the things or they cannot change them.
Like my Ivona voices that I use with Denise, they are very versatile and have the ability to change speed, pitch, volume.
But one little tidbit that I can give to you is if you're soundcard has the ability to turn on and off, an echo function, it makes the voice sound much more realistic.
The echo does not have to be very strong, just enough to give it better acoustics, like your voice naturally has when speaking in a room.
There are acoustic programs that you can purchase that allows you to enhance your audio output, like preset rock 'n roll, voice, classical music, etc. etc.
most good sound cards provide this software, so you can see it's just not tweaking the voice itself also tweaking your computer to get the voice to sound realistic.
And of course last but not least going into the dictionary editor of the voice and editing the voice to get it to sound more realistic or to just say the word more correctly.
That is a lot of work and in most cases happens over time if you like to just play around with that, personally I don't bother with getting all of the words the sound crystal clear.
As long as Sandy says it correctly I'm happy.
Sincerely, I hope you enjoyed the pronouns, here is a glass of adjectives to wash it all down.
C load.