Every once in a while, your cell phone may do something really annoying — it echoes your voice while on a call. The echo seems like a minor inconvenience but often overwhelms the call, requiring the speaker to hang up and try the call again. For some reason, the sound of our own voice coming back to us is too much for us to handle.

Imagine if that were weaponized.

Or, don’t imagine. There’s no need, because a team of Japanese researchers are working on that exact problem — minus the anecdote and plus actual science, of course.

The science is called “delayed auditory feedback.” The speaker speaks into a microphone and his or her voice is relayed back at a split-second delay. The replaying sound can be used to help those with stuttering problems, and has been used for those purposes for over three decades. But to those who aren’t used to the effect, delayed auditory feedback can be less-than-helpful. In fact, it can be downright maddening, to the point of interfering with our ability to speak.

In early 2012, the aforementioned researchers released a study (pdf) describing what they called a “SpeechJammer,” pictured above and described below.

[The SpeechJammer” is a device] which can be used to disturb people’s speech. In general, human speech is jammed by giving back to the speakers their own utterances at a delay of a few hundred milliseconds. This effect can disturb people without any physical discomfort, and disappears immediately by stop speaking [sic]. Furthermore, this effect does not involve anyone but the speaker. We utilize this phenomenon and implemented two prototype versions by combining a direction-sensitive microphone and a direction-sensitive speaker, enabling the speech of a specific person to be disturbed.

The SpeechJammer team released a video, embedded in a Wired article here, explaining the device, but it doesn’t say much more than what you’ve seen above. As Wired notes, the “weapon” is only a prototype for now, so you can’t buy one. But if you want to try the effect on yourself, you can, if you own an iPhone or Android-compatible device and a headset. Both have apps available (iPhone here, Android here or here), and if you want to see one of those apps in action, here’s a video of some guy trying — and failing — to review a gun (an actual, bullet-shooting one) while listening to his own voice on a slight delay.

Bonus fact : The word “infant” comes from the Latin term “infans,” which means “unable to speak.”

From the Archives: The Bourne Identity: The story of a person (not Jason Bourne) who suddenly lost the ability to speak (and a bunch of other abilities) and kind of recovered — except for the massive memory loss.

Related: TV-B-Gone — a keychain-sized universal TV remote mentioned in the above Wired article, which can be used to turn off televisions virtually anywhere. (Very fun at a Best Buy-like store.) 3.6 stars on 80+ reviews, may not work on a lot of newer televisions (per some of the reviews).