Conversation between two dolphins recorded for the first time. But what did they say?

A conversation between dolphins has been recorded for the first time. Researchers listened in on a pair of Black Sea bottlenose dolphins taking it in turns to produce a series of pulses, which they believe are individual words strung together to create sentences.

Published in the journal Physics and Mathematics, Vyacheslav A Ryabov, from the Russian Academy of Scientists, analysed multiple "non-coherent pulses" (NPs) between dolphins then matched them to the animals that produced them. He found the waveform and spectra of individual pulses changed significantly. The pulses, Ryabov claims, are words and that dolphins put them together to make sentences.

Furthermore, he said his experiments show how the dolphins would take it in turns to produce a pack of pulses and that they did not interrupt each other. He says this is "reason to believe that each of the dolphins listened to the other's NPs before producing its own", and that the exchange "resembles a conversation between two people".

"Each pulse in the NP packs that is produced by dolphins is different from another by its appearance in the time domain and by the set of spectral components in the frequency domain. In this regard, we can assume that each pulse represents a phoneme or a word of the dolphin's spoken language," he wrote.

The study said dolphins create words by combining and repeating specific pulses with different frequencies, levels and spectrums so they can distinguish words. It also said dolphin language has phonological and grammatical structures, so they can create an infinite number of words – therefore an infinite number of sentences.

The next step, Ryabov said, is creating dolphin translators so we can have conversations with them.

He wrote: "In this study, we carried out a reliable measurement of the mutually non-coherent pulses and their subsequent analysis as the most probable acoustic signals of the hypothetic spoken language of dolphins.

"As this language exhibits all the design features present in the human spoken language, this indicates a high level of intelligence and consciousness in dolphins, and their language can be ostensibly considered a highly developed spoken language, akin to the human language.

"This claim is supported by the fact that dolphins have possessed brains that are somewhat larger and more complex than human ones for more than 25 million years. Due to this, for further research in this direction, humans must take the first step to establish relationships with the first intelligent inhabitants of the planet Earth by creating devices capable of overcoming the barriers that stand in the way of using languages and in the way of communications between dolphins and people."