In November of 1978, an observer in a Boston institution hurriedly scrawled down a short note that, unbeknownst to them, would eventually send waves through the research field of language development.

Over the next several months, Hoover’s trainers at Boston’s New England Aquarium discovered that their unusual flippered friend could do far more than speak his own name. Rewarded with treats of fish whenever he spoke, the seal quickly began verbally greeting aquarium employees and patrons alike.

On these occasions, Hoover would adopt a straight-backed posture and square his shoulders (or, at least, the seal equivalent of shoulders) before yelping out phrases like “hello there, how are you,” “come over here,” or “get out of here” in a thick, rumbling New England accent, punctuated by raucous barks. He also appeared to be capable of “laughter,” scientists noted in a 1985 study, and once emitted a “blood-curdling scream” so alarming that an observer logged it as a data point in Hoover’s file.

Researchers later realized that Hoover had picked up several of these quirks from the Maine fisherman who had rescued him from the shores of Cundys Harbor when he was a pup. “Hoover sounds much like a male human with a Boston accent,” they wrote. Others, however, seemed to be Hoover-specific idiosyncrasies: “He often sounds somewhat inebriated,” the paper reads, “probably because of his tendency to slur together sounds representing separate human words.”

Unsurprisingly, Hoover’s remarkable ability to mimic human speech made him a hit—and people from all over flocked to Massachusetts to visit and converse with the world’s one and only “talking seal.” Hoover seemed to enjoy the spotlight, even staging the occasional fit, complete with “raspy breathing” and “strange cries,” to garner the attention of exasperated aquarium staff.

Even after Hoover died in 1985, scientists continued to puzzle over his startling verbosity. While Hoover was clearly producing the sounds of human speech, it was unclear how exactly he’d managed the feat—and researchers weren’t sure if this uncanny ability was just a fishy fluke.

Now, decades later, new research might finally help seal the deal. Reporting last week in the journal Current Biology, a team of scientists at the University of St. Andrews in the United Kingdom provides a fresh batch of evidence that seals can indeed learn and imitate many of the complex sounds fundamental to human speech. Not only can pups belt out clear vowels—a skill that many of our closest primate relatives can’t achieve—but they can also recognizably “sing” the first few notes of tunes like the Star Wars theme song and “Twinkle, Twinkle, Little Star.”

“This is the proof we’ve been waiting for,” says Morgan Wirthlin, a computational biologist studying language development at Carnegie Mellon University who was not involved in the study. “It’s long been thought that [seals and their relatives] have this incredible capacity for vocal learning...but this paper is the first to demonstrate it in a really clearly defined way.”

In the study, University of St. Andrews biologists Amanda Stansbury and Vincent Janik trained three young gray seals named Zola, Janice, and Gandalf to copy tones played from a computer by rewarding them with fish. At first, the researchers focused on notes that were within their species’ vocal repertoire, or something a seal might normally hear from a herdmate in the wild.

Once the seals were comfortable with this task, Stansbury upped the ante, and began including sounds at high, unfamiliar frequencies, as well as sequences that incorporated vowels from human speech. Stansbury even remixed some combinations to recall common jingles and songs that no seal would be expected to produce under natural circumstances.

The renditions were imperfect, and they might not sound as wicked smart as a Mainer from the 1970s. But the accuracy the seals achieved with unfamiliar melodies and human vowel sounds was impressive—especially considering that this is something that non-human primates tend to struggle with, says Stansbury, who is now at the El Paso Zoo in Texas. “Seals are the closest non-human analog we’ve found this behavior in,” she says.