Elements of Human Speech Discovered in Bird Babble
In recent years it has been becoming increasingly obvious that, complex as human language is, it might not be unique in the animal kingdom. Birds have separately evolved many of the same mechanisms to learn and create complex and meaningful sounds that they use to communicate. We have even discovered that the genes that allows them to do this is very similar to that found in humans (see Bird Song and Human Speech). Now researchers at the Universities of Exeter and Zurich have discovered that yet another property of human language that also exists in the bird world.
A phoneme is the smallest unit of meaningful sound a person can make. In English there are around 44 of them and by recombining phonemes you can create a range of novel and meaningful sounds. They are essentially the building blocks of language and now they have been discovered in birds.
The bird used in the study is the Chestnut-Crowned Babbler (Pomatostomus ruficeps), a medium-sized, dark brown bird from the arid zone of Australia. They don’t sing but they do make short calls to communicate with each other and each call is tailored to specific circumstances. The researchers record these calls and analysed them to identify two distinct and discreet sounds that they labelled A and B. Combining A and B in subtly different ways altered the meaning of various calls. For instance AB was discovered to be a flight call whilst BAB was used when feeding chicks. When researchers played back their recording of the two calls it elicited the expected behavioural responses in the birds. Then the researchers recreated the calls themselves. For example by slicing up the standard flight call into its constituent parts and recombining them they made a fake BAB call. When this was played back to the birds it also caused them to react as they has to the genuine BAB call proving that the A and B are discreet sound units that can be recombined to make novel calls, just like human phonemes.
This study is the first to actively identify, and test, phonemes in an animal language. It proves that just like us birds are able to recombine existing sounds to generate novel meanings. This has profound implications for our understanding of the evolution of birds, but also of our own linguistic abilities.
Reference: Engesser, S., et al. 2015. Experimental Evidence of Phonemic Contrasts in a Nonhuman Vocal System. Plos One. DOI: 10.1371/journal.pbio.1002171
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