Two Japanese researchers, Kazutaka Kurihara and Koji Tsukada, have developed the SpeechJammer, a speech jamming gun that can be used to disturb someone’s speech.
The way the device works is fairly straight forward, a direction sensitive microphone and speaker delay the speaker’s voice a few hundred milliseconds and then send the noise back to them, disturbing the speaker and effectively “jamming” there voice. There is no physical discomfort felt and no one else is bothered by the phenomenon.
The two researchers cited libraries and round-table discussions as ideal uses for the speech jamming gun. In a library, for example, the speech jamming gun can be used to get someone who is disturbing the peace to be quiet without having to contribute to the noise while telling them to quiet down. In response to their paper going viral, Kurihara and Tsukada put together a video showing the speech jamming gun in use: