As i said is a text-to-speech engine...you can't create your own voices. There is a male and female font for every language. You must buy every new font you want. Maybe the full version (all voice fonts) cost 295.00, Enterprise Version cost $69.5, include 2 fonts (male and female) for English language and some other tools. If you want to create your own voices you can export speech files in WAV/MP3 format and edit them with an audio editor (p.e Cooledit) to change voice colour, tone etc. The advantage of AT&T Natural Voices is the realism of exported speech, just check Microsoft Sam on your computer (control panel/speech) and ATT demo...