For half a century, the most famous fact about whales has been that they sing. In 1970 the biologists Roger and Katy Payne released an album of humpback song — eerie, looping, unmistakably deliberate — and the sound did what no argument had managed: it made millions of people feel that something vast and intelligent was down there in the dark. The record helped drive the Save the Whales movement, the Marine Mammal Protection Act, and the global ban on commercial whaling. Hearing the whales, it turned out, changed the law.
What we could not do, then or in the fifty years since, was understand them. That is the line a small constellation of scientists is now trying to cross, and machine learning is the instrument. The most ambitious effort, Project CETI — the Cetacean Translation Initiative, founded in 2020 — points artificial intelligence and gentle underwater robotics at the sperm whale, the animal with the largest brain on Earth, which lives in tight matrilineal families and speaks in patterned bursts of clicks called codas.
In November 2025, CETI's linguists at the University of California, Berkeley reported something that would have read as fantasy a decade ago. Sperm whale codas, long dismissed as a kind of morse code, appear to contain vowels: two distinct vowel-like sounds and several gliding diphthongs, produced on purpose, told apart by the whales, and traded back and forth in a way that looks like conversation. Their calls, the project's linguistics lead Gašper Beguš said, are more like “very, very slow vowels” — a complexity, he argued, that begins to approach human language. It builds on CETI's earlier finding that the clicks carry a combinatorial structure all their own: a kind of phonetic alphabet, with rhythm, tempo and ornament.
Whether another species has language has become a question of data, not of poetry.
Here is the part the wonder must not outrun: no one knows what any of it means — and some doubt the vowels are there at all. Veteran sperm-whale biologists have pushed back. Luke Rendell of the University of St Andrews, three decades with the animals, calls the vowel comparison “completely nonsense”; others suspect the pattern may be a recording artefact, or something the whales themselves do not attend to. Even CETI's own founder allows that the whales may not possess language as humans mean the word. What the team claims is narrower and firmer — that the sounds are structured, intentional, and told apart by the whales — not that anyone has decoded a single word. Translation, the thing the headlines always reach for, is not here, and may be years away or more.
CETI is not working alone. The Earth Species Project, backed by a clutch of technology philanthropists, has built the first large audio model trained on animal sound, and has cracked what acousticians call the “cocktail party problem” — teaching software to pull one whale's voice out of a chorus, the way you follow a single conversation across a loud room. And off the coast of Alaska, the Whale-SETI team — who study cetaceans partly as a rehearsal for the day we might have to recognise an intelligence not of this planet — played a recorded humpback greeting into the water and watched a whale named Twain circle their boat for twenty minutes, answering each call and matching the silences between them. It was, they were scrupulous to say, a greeting returned, not a conversation held.
What has actually changed is smaller than “talking to whales” and, in another sense, far larger. For the first time, the question of whether another species on this planet possesses something we would recognise as language is one that data and structure can be brought to bear on — even if, for now, the honest answer is that we do not know. CETI has already begun working with legal scholars on what an answer might mean for the rights of the animals themselves. Fifty years ago, merely hearing the whales sing was enough to change how we treated them. We may be about to learn what happens when we begin to understand the words — if, in the end, there are words to understand.
Sources
Sperm-whale “vowels” (the finding and the dispute): UC Berkeley Linguistics & Project CETI, “Vowel- and Diphthong-like Spectral Patterns in Sperm Whale Codas” (November 2025), ls.berkeley.edu; with the scientific pushback reported by Science News, sciencenews.org.
The phonetic alphabet (2024): MIT CSAIL & Project CETI, “Contextual and Combinatorial Structure in Sperm Whale Vocalisations” (Nature Communications), news.mit.edu.
Project CETI: the initiative's own account of its method and mission, projectceti.org.
AI across species: the Earth Species Project on its NatureLM-audio model and the “cocktail party problem,” happyeconews.com.
The humpback encounter: the SETI Institute, UC Davis and Alaska Whale Foundation Whale-SETI team on the exchange with “Twain,” seti.org.
Rights, ethics and the Payne legacy: Inside Climate News, “AI Is Decoding Whales' Communications,” insideclimatenews.org.
Where researchers disclaim decoded meaning, that caveat is reproduced rather than smoothed over.
Further Reading
This is a hopeful story, and hopeful stories need their skeptics. For readers who want to go deeper — into the research, the doubts, and the stakes — these are good starting points.
Go to the source: Project CETI (projectceti.org) and the 2024 sperm-whale “phonetic alphabet” paper via MIT CSAIL (news.mit.edu). The primary research, in the researchers' own words.
Across the animal kingdom: The Earth Species Project (overview), which aims to decode not one species but many, and built the first large audio model trained on animal sound.
The astrobiology lens: SETI Institute / Whale-SETI (seti.org), who treat whale communication as a rehearsal for recognising an intelligence that is not human at all.
The skeptics' case: Science News (sciencenews.org), where marine biologists including Luke Rendell and Stephanie King argue the “vowels” may be recording artefacts, not language — the essential counterweight to the wonder.
Rights and ethics: Inside Climate News (insideclimatenews.org), on what decoding whale communication could mean for the legal standing of the animals themselves.
The wonder, told long: Atmos (atmos.earth), a reflective feature on what “one step closer” really means — and why the absence of meaning, for now, is deliberate.