Freediving is easy. All you have to do, according to freediver extraordinaire, Stig Åvall Severinsen, is “learn to hold your breath as long as you can”. Simple.
The ability of two bottlenosed dolphins Tursiops truncatus to understand imperative sentences expressed in artificial languages were studied. One dolphin (Phoenix) was tutored in an acoustic language whose words were computer-generated sounds presented through an underwater speaker. The second dolphin (Akeakamai) was tutored in a visually-based language whose words were gestures of a trainer's arms and hands.
Excerpts from Current Biology, Volume 22, Issue 20, R860-R861, 23 October 2012
The whale lived among a group of dolphins and socialized with two female white whales. The whale was exposed to speech not only from humans at the surface -- it was present at times when divers used surface-to-diver communication equipment.
