Dolphins communicate with calves using baby talk.

A study published in the Proceedings of the National Academy of Sciences found that bottlenose dolphins use motherese, or baby talk, when communicating with their calves. The researchers analyzed recordings of 19 adult female dolphins and found that mother dolphins change the tone of their signature whistles when addressing their babies. The usage of child-directed communication is believed to enhance attention, bonding, and vocal learning, but researchers are not sure what the "mechanistic driver(s) or function(s) of" baby talk is for bottlenose dolphins.