The rapid clicks emitted by sperm whales may sound like meaningless background noise to us, but a new scientific analysis suggests they could be part of a complex communication system approaching the sophistication of human language.
According to researchers from CETI (Cetacean Language Translation Initiative), a U.S. non-profit organization dedicated to understanding the language of these creatures, the clicks, known as codas, are far more complex than a 2024 study indicated. That study found phonetic similarities between these tones and vowels in human languages.
Now, a new paper analyzing five features of coda tones reveals that these sounds are used in patterns that follow structural rules remarkably similar to those found in human speech.
Independent Evolution and Striking Similarity
“All five features have close analogues in the phonetics and phonology (sound system) of human languages, suggesting independent evolution of this system,” wrote the research team, led by linguist Jasper Begosh of CETI and the University of California, Berkeley. The team added: “As a result, sperm whale koda communication is highly complex and represents one of the closest parallels to the human vocal system among all the animal communication systems analyzed.”
Sperm whales live in close-knit, female-led family groups with strong cooperative relationships that give them a competitive advantage in the harsh seas. These complex social structures typically require equally sophisticated communication skills.
Decoding the Koda
In the new study, the team analyzed 3,948 koda tones from 15 whales recorded in the eastern Caribbean. They found that these tones fall into distinct categories that function much like vowels in human language, with consistent variations in length, patterns, and interactions with neighboring sounds.
The researchers identified two different types of koda tones based on their resonant frequencies; they named the first type “a-codas” and the second type “i-codas.” Remarkably, these sounds not only sound like vowels but also behave like them. For example, “a-codas” are longer than “i-codas,” and the latter have both short and long versions.
Moreover, each whale has its own unique timing for using these tones, and adjacent sounds can influence each other, much like letters in human language combine to form syllables.
A Communication System or a Language?
Researchers are cautious about calling what whales do a “language,” preferring to describe it as a “communication system,” a broader category under which language falls. For a communication system to be a language, it must combine sounds into structured and meaningful messages. Since we don’t yet know the “meaning” of these clicks, we can’t definitively define them as a “language.”
Nevertheless, this study brings us one step closer to the main goal of the CETI project: deciphering whale communication using machine learning to break down these communications into their smallest details and understand what whales are saying to each other.
The implications of this discovery are enormous. It not only tells us whether language is an exclusive feature of humans, but also gives us insight into how languages have evolved, and may open a door for us to communicate with other species that live in a way that is completely different from human culture.
