There's a long history of vocoders that use a mic instead of a tube:
from 'http://electronics.howstuffworks.com/gadgets/audio-music/talk-box.htm'
The talk box is not to be confused with other effects devices, such
as the wah-wah pedal or vocoder. A wah-wah pedal is another staple of
classic rock music, but musicians simply use a foot pedal
to make an electric guitar's frequency shift from treble to bass,
creating a "wah" sound." And a vocoder is a device that filters and
processes a human voice, and spits it out again sounding computerized
and robotic. Some also mistake the talk box for Auto-Tune,
a technique that has become popular in the past few years, especially
in pop music. Auto-Tune is a type of software that can help slightly
manipulate a singer's voice to hit the right notes.
The talk box
device, on the other hand, takes advantage of the unique qualities of
the human mouth and vocal tract and lends them to instruments.