Do shared vocal production and sound perception mechanisms support comparisons between animal signals and human phonology?

Shared vocal and auditory mechanisms give the comparison a physical basis

Vertebrate vocal production and auditory perception rest on physical structures and processes that can be studied across species. Research on vocal tract physiology and auditory perception in vertebrates provides evidence about how acoustic signals are generated and received, which is the starting point for any cross-species comparison [1]. Work on size information in communication sounds similarly traces how vocal tract mechanisms in humans and land animals shape the sounds that are produced and perceived [3].

Songbirds offer a particularly direct bridge to human speech. Their neural mechanisms of auditory perception and feedback-dependent imitation have been highlighted as a model for understanding human speech, because both involve learning to produce sounds by hearing and matching them [2]. This shared architecture of hearing-and-producing is what makes comparisons between animal signals and human phonology plausible in the first place.

In humans, perception and production are linked but not simply mirror images

A common assumption is that speech perception and speech production support each other, summarized as 'two sides of the same coin.' A 2024 review finds that this is partly true: there are many situations where the two modalities help each other, but there is also a growing body of evidence that they can operate independently or even in opposition, with production sometimes having a negative effect on perceptual learning at lexical and sublexical levels [4].

This matters for cross-species comparisons because it means that shared production and perception mechanisms do not automatically imply shared function. If human perception and production can diverge, then finding analogous circuits in a songbird does not by itself establish that the animal's signals work like human phonology [2][4]. The comparison is strongest at the level of mechanism—how sounds are learned, produced, and processed—rather than at the level of linguistic structure.

How we study animal communication shapes what we conclude about it

Comparisons between animal signals and human language are not neutral observations. The field of animal communication has been strongly shaped by a 'code model' that treats communication as information packets encoded, transmitted, and decoded, which standardizes methods but does not capture the nuance, ambiguity, or contextual variation seen in human communication [5]. Because animal and human communication are studied through different theoretical frameworks, apparent differences may partly reflect differences in method rather than differences in kind [5].

When these biases are acknowledged and approaches that move beyond searching for codes are incorporated, animal communication and human language may turn out to differ in degree rather than in kind [5]. For the specific question of phonology, this suggests that shared vocal production and perception mechanisms can support comparisons, but the strength of those comparisons depends on recognizing how the study frameworks differ.

Sources used in this answer

Related research questions