In addition to its normal underwater sonic communication path, the dolphin (Tursiops truncatus) can be trained to emit sounds from the blow-hole opened in air. By proper rewarding (positive reinforcement) and evocative techniques, such vocal emissions can be changed from the natural patterns. One such group of new sounds is said to resemble the human voice ("vocal mimicry"). Apects of these sounds which are physically determinable, specifiable, and demonstrable are the similarities in numbers of bursts of sound emitted by man and dolphin and in durations of successive emissions. In 92 percent of the exchanges the number of bursts emitted by Tursiops equalled, +/-1, the number just previously emitted by a man in sequences of one to ten bursts.