Idea for voice box with pitch

The pitch of a person's voice is determined by by the vocal cords or
vocal folds


image from http://en.wikipedia.org/wiki/Vocal_cord

When the folds close together they vibrate as air goes past
them.  The pitch is determined by the resonant frequency of
the folds.  So their closing must be determined by some
measurable nerve impulse.  This appears mostly possible
now through a metal probe placed into the adjacent muscle
tissue.  This could at some point be possible with external
electrodes.

That signal can then be processed to find a maximum and
minimum activity values that would fit to a pitch range. 
This would allow for that signal to be sent to an
electronically generated voice box that would have a
variable pitch.  This whole apparatus could be gently
strapped to the neck allowing the rest of the process
to occur in the mouth, like in a normal voice box device.

The smoker of yesteryear without a voice, could then
enjoy a much more expressive range of speech.  With
heightened control, the voice sound could become any
other sound, allowing the person to sing with any
musical instrument.