Baby Vocal

What vocal editing software does T-Pain use in the song “Hey Baby(Drop it to the Floor)”?
when t-pain is saying his line you cant tell, but at the end of the sentence there is a really cool sound and it changes tones. how do they do that? what software or vocal editing device do they use to do that?
for example t-pain says “Pump it from the side, pump it upside down
Or we can pump it from the back and the front” on the word front his voice changes tones and goes up.
this is the song im talking about http://www.youtube.com/watch?v=WfJTJztFEW4
in the example above it is from 0:44 – 0:52 in the youtube video
thanks
It’s a vocoder. There are a million different software and hardware applications that create this effect.
Tell Me Baby (Vocals Only) [Studio Version]