TECH - the Speech Jammer -Researchers develop 'SpeechJammer' gun

Researchers develop 'SpeechJammer' gun that can quash human utterances - if one speaks too long, the SpeechJammer aimed at the spaker very nearly instantly causing whoever is speaking to start stuttering then mumbling and then to stop speaking at all. SpeechJammer, a gun that can be fired at people to force them to stop speaking.The idea is based on the fact that to speak properly, we humans need to hear what we’re saying so that we can constantly adjust how we go about it, scientists call it delayed auditory feedback. When there is a slight delay (by 0.2 seconds) between the time the words are spoken and the time they are heard, people tend to get discombobulated and stop speaking.
How it works: a directional microphone and speaker are attached to a box that also holds a laser pointer and distance sensor and of course a computer board to compute the delay time based on distance from the speaker. To make it work, the person using it points the gun at the person talking, using the laser pointer as a guide, then pulls the trigger. It works for distances up to a hundred feet.

http://www.physorg.com/news/2012-03-speechjammer-gun-quash-human-utterances.html