The vision was set out in Life magazine in 1961 by Dr John C Lilly, an American physiologist, who was pictured at his laboratory in white shirt-sleeves with a microphone pressed against the blowhole of a young dolphin called Elvar.

Lilly was partial to hallucinogenic drugs and championed the recreational use of isolation chambers meant for sensory deprivation studies, but he also held a rare passion for dolphins. He devoted much of his life – and no fewer than five books – to the animals and dreamed one day of creating a common language we might use to converse with them. He even sketched designs for an aquatic lounge, where pods and people could meet for a natter.

And all for good reason, Lilly argued. Together, side-by-side with our marine mammal comrades, humans would be invincible. Or at least better at measuring ocean currents, collecting spent nose-cones from space rockets and fishing. "No human is as good at detecting, tracking, herding and catching fish as dolphins are. If we could get their cooperation, the whole fishing industry might be revised," he wrote.

Lilly's tireless bid to teach dolphins human speech met with failure, but we are living in different times. Denise Herzing, at the Wild Dolphin Project in Florida, and Thad Starner, an artificial intelligence expert at Georgia Institute of Technology in Atlanta, think they can resurrect Lilly's dream, if not his ocean-bound chatroom.

Later this year, divers will slip into the waters off the coast of Florida wearing a newfangled device that can listen and respond to wild dolphins by producing its own noises for words such as "seaweed". If the dolphins pick up the new language, the next step just might approach a rudimentary conversation.

But what are we to learn? The US Navy might want to ask Takoma, an Atlantic bottle-nosed dolphin, why he went awol in 2003 during his first mine-clearing operation in the Iraqi port of Umm Qasr. Maybe we can clear up once and for all whether a dolphin ever meant to foil a shark attack. More likely though, we won't so much talk to the animals, as open a window on their world, by learning how, and why, they talk to one another.