A recent study led by the University of California, Berkeley’s Linguistics Department and Project CETI has found that sperm whales may communicate in ways more similar to human language than previously believed. The research indicates that the acoustic features of whale calls resemble vowels, which are a key part of human speech.
“In the past, researchers thought of whale communication as a kind of morse code,” said Berkeley Linguistics Professor Gašper Beguš, who is also 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 identified two main patterns in whale sounds—an ɑ-vowel and an i-vowel—as well as several diphthong-like patterns. According to Beguš, sperm whales seem to exchange these sounds in what appears to be a form of 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 brings together experts from fields such as artificial intelligence, marine biology, cryptography, robotics and underwater acoustics to better understand how sperm whales communicate.
Beguš noted that whale vowels share many features with those found in human languages: length, timing, frequency and trajectory can all vary within both systems. In humans, these differences carry meaning; it is possible this could also be true for sperm whales.
“The spectral properties we discovered are very similar to human vowels. They correspond so closely that we can use human letters to describe them,” Beguš said. “Even the production of those sounds, which mirrors human vocal tract pulses, is similar to humans.”
The findings offer new insight into decoding how sperm whales communicate and raise broader questions about animal cognition and rights.
“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 hopes this research will encourage rethinking moral and legal distinctions between humans and other animals while supporting conservation efforts.
The team has spent five years observing sperm whale behavior using tags and drones to gather data on their communication patterns. They have recently begun learning how these calls function as part of whale social interaction.
To analyze the acoustic data from whale calls, Beguš used generative adversarial networks (GANs), a type of machine learning model designed to find patterns in large datasets by listening and imitating—much like how children learn language.
“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.”
With this approach, linguists studied not only individual vowel sounds but also combinations known as diphthongs—a shift from earlier studies focused mainly on clicks or inter-click intervals within whale calls.
“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, this work could transform both linguistics and our understanding of animal life by allowing linguistic analysis methods to be applied outside traditional human contexts.
“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.”
