The person who speaks holds the microphone which converts the voice message into electric static
signals flows back thru the hand of the speaker. Now the speaker's body has the electric static signals.
The speaker then touch another person's ear with a finger tip, the electric static signals flows
to that second person who receive the signals as in hearing the voice message.
http://www.disneyresearch.com/project/ishin-den-shin/ (youtube embedded)