Two Japanese researchers recently introduced a prototype for a device they call a SpeechJammer that can literally "jam" someone's voice – effectively stopping them from talking. Now they've released a video of the device in action.

"We have to establish and obey rules for proper turn-taking," write Kazutaka Kurihara and Koji Tsukada in their article on the SpeechJammer (PDF). "However, some people tend to lengthen their turns or deliberately disrupt other people when it is their turn ... rather than achieve more fruitful discussions."

The researchers released the video after their paper went viral Thursday, to the authors' apparent surprise. "Do you know why our project is suddenly becoming hot now?" asked Kurihara, a research scientist at the National Institute of Advanced Industrial Science and Technology in Tsukuba, in an e-mail exchange with Wired.com. (Kurihara's partner Tsukada is an assistant professor at Ochanomizu University in Tokyo.)

The design of the SpeechJammer is deceptively simple. It consists of a direction-sensitive microphone and a direction-sensitive speaker, a motherboard, a distance sensor and some relatively straightforward code. The concept is simple, too – it operates on the well-studied principle of delayed auditory feedback. By playing someone's voice back to them, at a slight delay (around 200 milliseconds), you can jam a person's speech.

Sonic devices have popped up in pop culture in the past. In sci-fi author J.G. Ballard's short story "The Sound-Sweep," published in 1960, a vacuum cleaner called a "sonovac" sweeps up the debris of old sounds. The wily German composer Karlheinz Stockhausen had plans for a "sound swallower," which would cancel unwanted sounds in the environment using the acoustic principle of destructive interference. And in 1984 German film Decoder, special yellow cassette tapes play "anti-Muzak" that destroys the lulling tones of Muzak, stimulating diners at a fast-food restaurant to throw up en masse and start rioting.

But instead of sci-fi, the Japanese researchers behind the SpeechJammer looked to medical devices used to help people with speech problems. Delayed auditory feedback, or DAF, devices have been used to help stutterers for decades. If a stutterer hears his own voice at a slight delay, stuttering often improves. But if a non-stutterer uses a DAF device designed to help stutterers, he can start stuttering – and the effect is more pronounced if the delay is longer, up to a certain point.

"We utilized DAF to develop a device that can jam remote physically unimpaired people's speech whether they want it or not," write the researchers. "[The] device possesses one characteristic that is different from the usual medical DAF device; namely, the microphone and speaker are located distant from the target."

Being at a distance from the target means it's possible to aim the device at people who are several feet away – sort of like a TV B-Gone, but for people. Bothered by what someone at a meeting is saying? Point the SpeechJammer at him. Can't stand your nattering in-laws? Time for the SpeechJammer. In the wrong hands – criminals, for instance, or repressive governments – the device could have potentially sinister applications. For now, it remains a prototype.