Dolphins make a wide array of sounds, including clicks, moans, chirps,creaks, barks, squeaks, yaps, mews, and whistles. Dolphins use clicking noises in echolocation, which bounce off objects underwater. This allows them to navigate, identify prey and friends, and avoid obstacles and predators.
Dolphins use whistles to maintain contact within their pod or when meeting other pods of dolphins.
Their whistles may signal danger, a call for help, or simply identification. Scientists think that each dolphin has its own signature whistle, sort of like our names. Whistles may also help dolphins hunt cooperatively and coordinate migratory movements. Louis Hermann of the University of Hawaii's Kewalo Basin Marine Mammal Lab is a leader in the field of animal-language research. He does not believe dolphins have their own language, but he has been able to teach artificial language to four dolphins at his lab.