exeterdad has built the SpeechTools libraries and Festival, both of which can be found in the testing repos along with the source code:
festival: The Festival Speech Synthesis System.
festival: Festival offers a general framework for building speech synthesis
festival: systems as well as including examples of various modules. As a whole
festival: it offers full text to speech through a number APIs: from shell level
festival: though a Scheme command interpreter, as a C++ library, from Java
festival: and an Emacs interface. Festival is multi-lingual. The system is
festival: written in C++ and uses the Edinburgh Speech Tools Library.
festival: License: X11-type. Unrestricted commercial and non-commercial use.
festival: Website: http://www.cstr.ed.ac.uk/projects/festival
festival: Authors: See Docs <firstname.lastname@example.org>
speech_tools: The Edinburgh Speech Tools Library.
speech_tools: Is a collection of C++ class, functions and related programs for
speech_tools: manipulating the sorts of objects used in speech processing. It
speech_tools: includes support for reading and writing waveforms, parameter files
speech_tools: (LPC, Ceptra, F0) in various formats and converting between them.
speech_tools: License: X11-type. Unrestricted commercial and non-commercial use.
speech_tools: Website: http://www.cstr.ed.ac.uk/projects/speech_tools
speech_tools: Authors: See Docs <email@example.com>
Post and comments of feedback for these packages here.