The Fedora Project offers users the ability to use accessibility profile tools depending on the type of disability. This provides users the accessibility features they need in order to use the system on a daily basis for all of their computing needs.
KTTS -- KDE Text-to-Speech
KTTS is a subsystem within the KDE desktop for conversion of text to audible speech.
The Festival Speech Synthesis System
Festival offers a general framework for building speech synthesis systems as well as including examples of various modules. Festival is multi-lingual (currently English (British and American), and Spanish) though English is the most advanced.
Fedora users can install them via
$ su - (enter root password)