Readers of this blog will, by virtue of being able to read it at all, be familiar with the complex construction of language: sentences can be broken down into words, which can themselves be broken down into syllables or uninterrupted sounds. Many, but perhaps not all, will also be familiar with the concept of “phonemes”, which are the component parts of syllables, represented as the somewhat arcane-looking symbols of the International Phonetic Alphabet (IPA) found as a pronunciation guide in dictionaries, each symbol corresponding to a different phoneme. A more precise definition might be that they are the smallest parts of language that denote a change in meaning.
That’s the case for humans at least, but for animals, the situation is somewhat different. Animal communication is usually divided into “calls” and “songs”, with calls being short, distinct and usually monosyllabic sounds with a specific meaning. Songs are more complex and can accordingly convey more complex meanings; but importantly, they comprise a number of syllables and each syllable represents a distinct unaltered unit that carries the same meaning each time it arises. For animals, therefore, it seems that the syllable is the smallest unit that changes meaning – phonemes and syllables are the same thing. At least, it did seem this way: a new paper in BMC Biology from Jansen and colleagues shows that the banded mongoose constructs single-syllable calls from two distinct parts, one more noisy and consonant-like, and the other more harmonic and vowel-like, which encode two different pieces of information, identity and activity (for example whether the mongoose is digging or moving).
So maybe phonemes and syllables can be distinct for animals after all, as ably explained by Tecumseh Fitch in an accompanying commentary that sets the paper into the context of research on animal communication so far.
While the usual proscriptions about extrapolating from animal to human behaviour apply, it will be interesting to find out exactly what mongooses can tell us about the evolution of language and communication, and also to revisit communication in other animals that may be using subtle phonemes that have previously been missed.