The Ishin-Den-Shin technology uses a standard microphone to record audio and then converts it into an inaudible signal transmitted through the body of the person holding the microphone.  http://www.bbc.co.uk/news/technology-24031948 When they touch someone’s earlobe, an organic speaker is formed and the sound becomes audible, effectively whispering a message into that person’s ear.
The sound can be passed from person to person using any physical contact.
The technology was developed at Disney Research in Pittsburgh, PA.
It records sounds through a device fitted to the microphone that creates a “modulated electrostatic field” around the user’s skin.
“When touching another person’s ear, this modulated electrostatic field creates a very small vibration of the earlobe,” Disney Research says on its website.
“As a result, both the finger and the ear together form a speaker, that makes the signal audible for the person touched.
“The inaudible signal can be transmitted from body to body, using any sort of physical contact.”
The technology would be “almost magical and appear to come from nowhere”.
Ishin-Den-Shin is a Japanese mantra that translates as, “What the mind thinks, the heart transmits,” and represents unspoken mutual understanding.