From LQWiki

With kmouth, you can make the computer speak for you using its sound system.

Installation

• install festival
• install the KDE accessibility package
• start kmouth
• chose festival as speaking software

Fun with kmouth

The following command tells you witty sayings every 30 seconds, using the KDE speech daemon:

while true; do dcop kttsd KSpeech sayText "`fortune`" 0; sleep 30; done

See also

• festival