The Talk Box
Even the human voice couldn't escape the electric edge of rock.
Readers who remember Peter Frampton's meteoric rise to stardom in 1976 (and subsequent descent into obscurity following his role in the movie [[xref:http://en.wikipedia.org/wiki/Sgt._Pepper%27s_Lonely_Hearts_Club_Band_(film)| Sgt. Pepper's Lonely Hearts Club Band|Sgt. Pepper's Lonely Hearts Club Band]] in 1978) will likely have fond (or not-so-fond) memories of his use of the Talk Box.
The Talk Box uses the shape and position of the user's mouth and tongue to change the sound of an instrument (usually an electric guitar) in the same way that the human voice changes, ultimately making it sound like a talking guitar.
The Talk Box isn't seen so much in rock these days, but voice manipulation remains very much in vogue — just listen to a T-Pain album or watch [[xref:http://www.youtube.com/view_play_list?p=736C3116AD309B58|Auto-Tune the News|Auto-Tune the News]].