Many TTS soond incredibly robotis, or all, comprehensive of SIRI and GOOGLE VOICE.
I think that if a TTS has the fortune to focus around an argument, thebest would be to record some hundred words, with perfect sound, instead to synthesize the words.
A good example are many navigation systems that not synthesize the words from the letters, but they have pre recorded the full words, and they can do it easily because they use few words: TURN LEFT, TURN RIGHT and few more.
So.. where I cna find a TTS that permit me to add my custom words instead to synthesize the words from every single letter?