A new study has found that dolphin mothers also use a kind of high-pitched baby talk with their kids. Researchers recorded the signature whistle of 19 female bottlenose dolphins in Florida, when they were accompanied by their young offspring and when swimming alone or with other adults. The dolphin whistle is a unique and important signal _ akin to calling out their own name. A study published Monday found that the mother’s whistle pitch is higher and her pitch range is greater when around only her calves. Why people, dolphins or other creatures use baby talk isn’t certain, but scientists believe it may help offspring learn to pronounce novel sounds.
This is just conjecture, but:
It’s possible that it helps [proto-]language acquisition, but I feel like babytalk might also directly help the adult speaker. I’m saying that because plenty people use a babytalk-like register to address pets, that won’t benefit from it.
Perhaps the usage of babytalk reduces the cognitive burden associated with changing your behaviour to a way that is suitable for the presence of children nearby?