Formal models of Structure Building in Music, Language and Animal Songs

TL;DR

This paper reviews formal models of structural complexity in language, music, and animal songs, comparing their similarities and differences, and discusses the applicability of the Chomsky hierarchy and its extensions.

Contribution

It synthesizes models of structure building across language, music, and animal communication, highlighting the limitations of the Chomsky hierarchy and proposing avenues for future research.

Findings

Music and animal songs are more comparable than language in structural complexity.

The Chomsky hierarchy has limitations in modeling music and animal communication.

Extensions of the CH can better address the complexities of non-linguistic communication.

Abstract

Human language, music and a variety of animal vocalisations constitute ways of sonic communication that exhibit remarkable structural complexity. While the complexities of language and possible parallels in animal communication have been discussed intensively, reflections on the complexity of music and animal song, and their comparisons are underrepresented. In some ways, music and animal songs are more comparable to each other than to language, as propositional semantics cannot be used as as indicator of communicative success or well-formedness, and notions of grammaticality are less easily defined. This review brings together accounts of the principles of structure building in language, music and animal song, relating them to the corresponding models in formal language theory, with a special focus on evaluating the benefits of using the Chomsky hierarchy (CH). We further discuss common misunderstandings and shortcomings concerning the CH, as well as extensions or augmentations of it that address some of these issues, and suggest ways to move beyond.