KTTS is a KDE application for the conversion of text into audible speech. Currently, since KDE 3.4, you can use KTTS to speak any text from the Klipper, the KDE clipboard, any text from a plain text file (using Kate or otherwise), speak any portion of text from a HTML page in Konqueror, and much more.
To get KTTS up-and-running you will need to start by running
kttsmgr
, the KDE Text-to-Speech manager.