It actually dates back to 1984, when scientists at the National Marine Mammal Foundation started to notice human-like voice coming from the whale and dolphin aquarium, but for some reasons they reported it only now, five years after the beluga who tried to communicate died. Still it is a quite interesting read, and the recording is funny, although hard to guess what the beluga is actually telling
A whale with a distinctly human-like voice
Current Biology - Spontaneous human speech mimicry by a cetacean
A whale with a distinctly human-like voice
Current Biology - Spontaneous human speech mimicry by a cetacean