I’m the ten zillionth person to post this but I couldn’t help joining in. It’s not too surprising now when certain birds mimic human speech, but it’s amazing to hear a white whale attempt it.
This article gives interesting details. The whale “spent long periods in close contact with humans, listening to them from both above and below the surface.” This incident, recorded many years ago, is not the only white whale in captivity to copy human speech. The whale was required to go several octaves lower than its typical sounds to achieve the mimicry.