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.