Speech Synthesis (As In Portal)?

I’m looking for a way to reproduce pitch shifted/ almost robotic voice effect of GLADOS character in the Portal game series (for those who’ve played it ;) ).
Is there an easy way to do it? Is there some free VST for this?

its the voice of Ellen McLain, who is speakin in such a monotonic way, that it was easier to mimic a real robot voice.
iirc Mike Morasky (valves audio engineer) used protools for portal.
my guess, its just Mclains voice and DAW handcrafting with PTs pitch- and time- shift algo.

free pitch- shifter http://www.gersic.com/plugins/index.php?daCat=10
also check the granular stuff like ktgranulator or ggrain by gvst

Also try using http://www.gvst.co.uk/gsnap.htm or autotune or melodyne or similar to flatten the pitch of the speaker and introduce little flutters. The metallic tone is up to you.

You might also try adding a comb filter after what was already suggested above for a nice sci-fi effect.

Here’s a pretty nice tutorial I saw on YouTube years ago:

The tutorial is based on Melodyne, which is not free, but maybe you can take some tips from it to recreate the same effect with other free software.