if u got a mobile phone with a really loud ring tone turn it up full blast. then stick it right in your mouth and make movements with your mouth. the sound it makes is the basis of the talkbox.
so what happens is the sound from ur amp goes into a tube that goes into ur mouth. then you put ur mouth next to a microphone and that microphone is going into a PA or a stereo or something so whats coming outta ur mouth can be heard.
go to
www.jimdunlop.com or something and look at the heil talkbox there. download the instruction manual and it has the proper way to set up talkboxes.
and they seem harder to use than they look.......it'd be sorta like singing and playing at the same time. depends how hard the vowels or consonants your trying to create with it.