Tinkering with Compressed Speech

[Tim Chase]

I don't know whether you've got specific goals for this--if it's
  just space-compressed, there's an OSS packaged by the name of
speex (www.speex.org) which gets an exceptionally good
compression ratio on speech.  For speech, speex gets 2-4 times
the compression ratio of OGG with about the same quality
(however, compressing non-speech like music comes out really
dumpy sounding).  If you just want to speed up playback without
pitch shifting, that's another matter.  The "sox" package has an
option for speeding up playback without changing the pitch.  You
can learn more about sox on its website at SourceForge
(http://sox.sourceforge.net).  There's even a good section in the
Linux Cookbook on using Sox:
http://www.dsl.org/cookbook/cookbook_29.html#SEC404

A combination of speex (to store it and then play it back to a
file) and sox (to take the output "file" piped from the
"speexdec" decoder, and play it back at an altered rate) could be
a handy combination.

However, if your purpose is just to have fun, keep hacking!
(grins)  Might even find some handy stuff in the source code of
either app.

Hope this helps you in your quest for speech compression,

-tim