The voices available to use for TTS depend on which have been installed. These are available from many vendors. Some are installed along with Windows if the option was not deselected during the install of the OS.
How do I get a list of the voices in my system?
There are two ways to get the list of voices on your system. Note that when coding, you must specify the name of the voice exactly as it appears in the list that Windows recognizes.
Also, the voices available are the ones installed on the Voice Elements Server, not the client if your application is running on a separate machine.
Windows Control Panel
On the server machine, the list of all installed voices may be found in Control Panel > Speech > Text-to-Speech Tab. There is a voice drop down showing all the voices available to you. For more information, see Microsoft’s article “How to configure and use Text-to-Speech in Windows XP and in Windows Vista“.
Voice Elements Server Log
You may also open the ElementsServer.log file located in the root installation directory of the Voice Elements server. The default directory is c:\Program Files\Inventive Labs\Voice Elements Server. On start up, the server lists available voices. Do a search for “voices” and you will find the list of the TTS voices available.