Sept. 21 (UPI) -- Some 80 different human cultures use whistling to communicate across long distances.
In a new paper, published Tuesday in the journal Frontiers in Psychology, scientists argue these languages can aid the study of dolphin communication.
Whistled languages mostly evolved in places where humans live, move and work across rugged landscapes and high elevations. High frequency whistles can travel long distances and help humans communicate without lines of sight.
Though each whistled language is unique to the culture from which it evolved, they all follow a basic formula, with whistled melodies substituted for the syllables of simplified words.
Whistled languages can be used to communicate surprising amounts of detail. In Turkey, speakers of whistled Turkish can comprehend up to 90 percent of common sentences.
Scientists have previously looked to whistled languages for insights into the ways the human brain processes language.
In the 1960s, French researcher René-Guy Busnel, an expert on whistled languages, suggested they might help scientists uncover the evolutionary origins of bottlenose dolphin communication.
In the new paper, the research team -- featuring several of Busnel's former colleagues -- looked at how whistled languages might highlight similarities in the ways bottlenose dolphins and humans communicate.
One of the difficulties of studying both dolphin and human whistles is that phonemes, units of sound that distinguish one word from another, are not easily identifiable.
Sonograms of whistled communication, images of the communicated sounds, feature successions of phonemes, which are often not separated by silences.
"By contrast, scientists trying to decode the whistled communication of dolphins and other whistling species often categorize whistles based on the silent intervals between whistles," study co-author Diana Reiss, a professor of psychology at Hunter College in the United States, said in a press release.
Future investigations of whistled languages, whether in the context of human or dolphin communication, must utilize both sound recordings and sonograms in order to illuminate the ways whistled languages are conveyed structurally.
In followup studies, researchers said they hope to leverage a growing database of whistled languages with a similarly large compilation of dolphin whistle data.
"On these data, for example, we will develop new algorithms and test some hypotheses about combinatorial structure," said lead study leader Julien Meyer, a linguist at the French National Center for Scientific Research.
In order to decipher dolphin speech, researchers must identify the language's building blocks -- the phonemes that can be combined to form and transport meaning.
"We would need to know what the minimum unit of meaningful sound is, how they are organized and how they function," Reiss said.