There was a Bugtraq local exploit alert for speechd versions up to 0.54. Download version 0.55 (not yet tested).
speechd - Implements /dev/speech (any
text written to /dev/speech will be spoken aloud).
Thu Sep 13 14:52:44 EDT 2001
The speechio.faq has info on increasing the volume of speech, and
dealing with RedHat's broken /etc/hosts file, which will give you errors similar to
"rejected from localhost.localdomain not in access list".
rsynth speech synthesis package.
Festival with a high quality voice is recommended.
RedHat packages exist for both Festival and rsynth.