Voice parameter adjustment for gender & age

Allow the user to set voice parameters for gender & age. This will typically only need to be set once per user, to provide a more natural (or at least less-unnatural) match to their own voice, helping them to feel more comfortable using the software to communicate. The current voice parameters are hard-coded to simulate the voice of a young adult woman, for Cynthia H., our very first user.
Users will probably want to test play some voices to find the best match, so perhaps a test phrase would help with this.
Most people could be covered with these two parameters: gender and pitch.
These two factors do interact, but Espeak provides pretty good options for these: http://espeak.sourceforge.net/commands.html