Scientists try decoding monkey language!

​London: Scientists are studying the form and meaning of monkey calls using methods from theoretical linguistics, in order to better understand the language of the primates. It has long been known that monkeys convey information through alarm calls, but now a combined team of linguists and primatologists has laid the groundwork for a systematic 'primate linguistics.'

Researchers have brought the general methods of contemporary linguistics to bear on monkey morphology (pertaining to the structure of calls), syntax (how the calls are put together into sequences), and semantics (what calls and call sequences mean), building on several earlier studies conducted within primatology.

"We can now study the form and meaning of monkey calls using methods from theoretical linguistics," said Philippe Schlenker, from the National Centre for Scientific Research (CNRS) in France. "Using this approach, we can compare one monkey species to another and see, for instance, that some of their calls have been preserved over three million years," said Schlenker, who is also a professor at New York University.

Monkey languages in no way have the complexity of human language, but that they still display exciting and sometimes challenging formal properties, researchers said. With respect to primate morphology, Campbell's monkeys, found in Africa, make a distinction between roots (especially "hok" and "krak") and suffixes ("-oo"), and their combination allows the monkeys to describe both the nature of a threat and its degree of danger.

For instance, "hok" warns of serious aerial threats - usually eagles - whereas "hok-oo" can be used for a variety of general aerial disturbances; in effect, the suffix "-oo" serves as a kind of attenuator. The same monkeys display a limited amount of dialectal variation in the meaning of a call, "krak," which has a leopard-related meaning in one site and a 'general alert' meaning in another, from which leopards are absent. However, calls are also combined in interesting ways - a possible instance of elementary 'primate syntax,' which raises questions about how the meanings of monkey calls are combined ('primate semantics').

Campbell's monkeys have "boom" calls, which usually come in pairs - but these are constrained to appear at the beginning of call sequences. In Putty-nosed monkeys, "pyows" are used as general calls ('there is an alert'), while "hacks" are usually raptor-related (eg 'there is an eagle').

But a small number of "pyows" followed by a small number of "hacks" have a distinguished status and trigger group movement ('let's move!'). "These findings show that methods from linguistics can illuminate communication systems beyond human language and in the future they might find further domains of application beyond primates," said Schlenker.