By studying trained dolphins and other free-roaming odontocetes, researchers have discovered that these animals, like us humans, have at least three vocal registers: the rhythmic one (or ‘vocal fry’, which produces the lowest tones), the so-called ‘chest voice’ ‘ (which we normally use to speak) and falsetto (which produces higher frequencies). The rhythmic register “is often used in American English,” explains Elemans. “Kim Kardashian, Kate Perry and Scarlet Johannsen are well known for using this register.” According to the study, odontocetes use such a register to produce the sounds necessary to locate prey with echolocation. In the past it was assumed that they produce them with the larynx, just like other mammals, but then it was understood that it would be impossible when the animal is at great depths with water pressure that prevents it from having an adequate respiratory volume in the lungs .
Everything actually takes place in the nose and Danish researchers are the first to demonstrate how the mechanism works. During echolocation, odontocetes pressurize the air in the nose and pass it through structures called ‘phonic lips’ that vibrate just like our vocal cords. Their acceleration produces sound waves that travel across the skull and toward the front of the head. These cetaceans use their phonic lips to produce two other registers (chest voice and falsetto) to communicate with their fellows through a range of even complex sounds that some species (such as killer whales) learn and pass on as we humans do with the dialects.