Whale learns to talk in 'human' voice - video
The sounds from Noc made a diver believe that another person was telling him to get out of the water, researchers said.
A paper titled 'Spontaneous human speech mimicry by a cetacean' has been published in the latest issue of Current Biology.
"Although dolphins (Tursiops truncatus) have been trained to match numbers and durations of human vocal bursts and reported to spontaneously match computer-generated whistles, spontaneous human voice mimicry has not previously been demonstrated," the authors explained.
"Hitherto no acoustic recordings have shown how such sounds emulate speech and deviate from the usual calls of the species.
"We report here sound recordings and analysis which demonstrate spontaneous mimicry of the human voice, presumably a result of vocal learning, by a white whale."