[mbzbnejs] Transmitting whispers and shouts

Create a communication device with which the speaker can speak extremely softly, e.g., whisper or mumble, and a listener on the other end can hear it intelligibly.  However, if the speaker were to speak loudly, the listener's can also comfortably hear it without getting eardrums blown out.

Can the speaker speak softer than a whisper?  Perhaps some lip reading sensor as the speaker simply mouths the words.