Dolphins are the world's second brightest creatures after humans and have many brain features associated with high intelligence.
So clever are the aquatic mammals that scientists have frequently communicated with those in captivity by rewarding their responses with fish.
But behavioural biologists have now carried out two-way communication with dolphins in the wild in the first study of its kind.
Dr Denise Herzing and colleagues at the Wild Dolphin Project in Jupiter, Florida, established a shared, primitive form of language using sounds, symbols and props.
'Many studies communicate with dolphins, especially in captivity, using fish as a reward,' Dr Herzing told Wired.com. 'But it’s rare to ask dolphins to communicate with us.'
The experiment revolved around both dolphins and humans asking each other for props such as balls and scarves.
A large underwater keyboard formed the focus of the study; each key was painted with a different symbol and emitted a precisely pitched whistle.
When a dolphin pressed a certain key with her nose, researchers would throw the corresponding prop into the water. Should the dolphin instead decide to whistle the pitch that a certain key would emit, then that prop would be thrown in.
Over the course of three years, the scientists played with the dolphins for 40 half-hour sessions.
They found that while young males were less interested in interacting with humans, young females enjoyed the game.
Dr Herzing said: 'This is when the females have a lot of play time, before they are busy being mothers.'
The sessions were at the most successful when the biologists had swum slowly with the dolphins beforehand, particularly if they had made eye contact and mimicked each other's movements.
Highlighting their social tendencies, the spotted dolphins Dr Herzing's team was playing with even recruited another species, bottlenose dolphins, to play the game.
The study was published in the Acta Astronautica journal.