A new study by the University of California, Berkeley’s Linguistics Department and Project CETI has found that sperm whales communicate using acoustic properties similar to those found in human language. The research suggests that whale calls are not just random noises or simple codes but share key features with human vowels.
“In the past, researchers thought of whale communication as a kind of morse code,” said Berkeley Linguistics Professor Gašper Beguš, who is the linguistics lead at Project CETI. “However, this paper shows that their calls are more like very, very slow vowels. This suggests a complexity that approaches human language.”
The study, titled “Vowel- and Diphthong-like Spectral Patterns in Sperm Whale Codas,” identified two specific patterns—an ɑ-vowel and an i-vowel—as well as several diphthong-like forms within whale sounds. According to Beguš, these sounds appear to be exchanged between whales in what resembles dialogue.
“The whales’ production of the ɑ-vowel, i-vowel and diphthongs is likely controlled,” Beguš said. “This is true across almost all whales. We don’t understand the meaning yet, but we know that whales produce these sounds intentionally and we know that they differentiate between them.”
Project CETI’s research team includes artificial intelligence experts, marine biologists, cryptographers, roboticists, and underwater acousticians working together to decode how sperm whales communicate. Over five years, they have used tags and various types of drones to observe whale behavior and vocalizations.
Beguš explained that the similarities between whale vowels and those in human speech include differences in length, timing, frequency, and trajectory—characteristics known to carry meaning among humans. He noted: “The spectral properties we discovered are very similar to human vowels. They correspond so closely that we can use human letters to describe them. Even the production of those sounds, which mirrors human vocal tract pulses, is similar to humans.”
He added that understanding this level of complexity could have wider implications: “We’re thinking deeply about what finding these human-like structures means for the legal rights of animals,” said Beguš. “This paper prompts questions like, for example, what is language? Is there anything uniquely human about language, or is it just a continuum? What does that mean for the law?”
Project CETI aims ultimately to translate sperm whale communication into a form humans can understand more fully. Their recent advances were made possible by applying machine learning techniques such as generative adversarial networks (GANs) to analyze whale sound data—a method inspired by how children learn languages through listening and imitation.
“GANs can discover words and meaningful structure. When designing the model, we asked whether they could do that in whales as well,” Beguš said. “We still need human researchers to analyze the details, but they help us look in a specific direction.”
While previous studies focused mainly on analyzing clicks—the rapid pulses used by whales—this new approach examines vowel-like elements within their calls for greater insight into potential meaning.
“Before, researchers focused primarily on whale clicks and inter-click timing,” said Beguš. “Analyzing vowels adds a completely new dimension that brings much more complexity.”
According to Beguš and Project CETI’s findings so far—including their earlier identification of over 150 click patterns—the work may shift not only our understanding of animal communication but also open up broader discussions about animal cognition and rights.
“This work is so important because it helps you relativize your own position as a human,” said Beguš. “We exchange inner worlds through speech, through vowels and consonants. This is a small step towards understanding the inner worlds of animals, their cultures and their intelligences.”
