Abstract: The communicator comprises a casing with extending bits for clenching between a diver's teeth in a manner such that the diver can speak into an air chamber within the casing. An acoustical diaphragm within the casing absorbs acoustical energy in the air chamber. An emitter element in turn has at least one surface in direct physical contact with the surrounding water and is connected to the diaphragm through a mechanical means designed to provide an acoustical impedance match between the acoustic energy in the air chamber and the acoustic energy generated in the surrounding water by the emitter thereby maximizing the energy transfer from the diver's voice to the surrounding water. The casing and bit held in the diver's teeth serve as a receiver for acoustical energy in the water which is conducted through the bit and diver's teeth to his auditory senses.