Festival offers a general framework for building speech synthesissystems as well as including examples of various modules. As a wholeit offers full text to speech through a number APIs: from shell level,though a Scheme command interpreter, as a C++ library, and an Emacsinterface. Festival is multi-lingual (currently English (US and UK)and Spanish are distributed but a host of other voices have beendeveloped by others) though English is the most advanced.
The system is written in C++ and uses the Edinburgh Speech Toolsfor low level architecture and has a Scheme (SIOD) based commandinterpreter for control. Documentation is given in the FSF texinfoformat which can generate, a printed manual, info files and HTML.