http://code.google.com/p/axtk/
What is AxTk?
AxTk (pronounced Ay Ex Tee Kay)
is an open source, C++ add-on for wxWidgets that helps developers create highly accessible, talking applications for users with impaired vision. It may also be useful for other impairments that benefit from a simplified user interface.
AxTk features a new menu-based system that is easy to learn and use, in addition to providing adaptation for some existing GUI controls and dialogs. The developer can choose whether to use the menu system, or to adapt an existing application UI, or use a combination of methods.
AxTk is cross-platform (tested so far on Windows XP, Linux and Mac OS X 10.5), and includes text-to-speech classes with the ability to drive SAPI 5, Apple Speech Synthesis Manager, eSpeak, and Cepstral. Other speech engines can be driven by writing additional handlers.
Note that AxTk is a work in progress and the API is subject to change.