To what extent are phonological inventories complex systems?

Abstract

© Salikoko S. Mufwene, Christophe Coupé, and François Pellegrino 2017. Complex systems are often defined on the basis of the interactions that take place between their constituents. This approach echoes the founding principles of structuralism in linguistics more than a century ago. It was indeed Ferdinand de Saussure, in his 1916 Cours de linguistique générale, who defined any language as a system whose building blocks only exist in the structure of their relationships, be they of equivalence or opposition. Structuralism as a theoretical framework in linguistics initially developed more at a synchronic level, before the dynamical phenomena leading to the emergence, preservation, or disruption of structures were addressed. Concepts such as retroaction and self-organization appeared in the wake of cybernetics in the 1950s and 1960s (Ahsby, 1947; Wiener, 1961). Further developments led to notions such as emergence, dynamical equilibrium, chaos, self-organized criticality, and so on. These concepts soon spread to various scientific fields, including the life sciences and the humanities; their ubiquity is one of the pillars of today’s generic “theory of complex systems,” which to some extent succeeded in adding a dynamical perspective to the time-frozen structures of structuralism. In the field of linguistics, considering phonological inventories in the light of the theory of complexity is not new, and they may be the first linguistic structures that benefited from its explanatory power. The notion of self-organization appears in a 1983 paper on phonological universals (Lindblom et al., 1983): on the basis of observed regularities in the inventories of the world’s languages, the location of vowels in the vocalic triangle was accounted for by a self-organized process. According to it, vowels found their optimal positions by maximizing the perceptual distances between them. This maximal dispersion was related to the idea of maximal perceptual contrast: words whose sounds are maximally distant at the perceptual level are easier to discriminate. Lindblom et al.‘s approach was further refined along different lines, taking consonants into account (Lindblom & Maddieson, 1988), refining the notion of perceptual distance, and shifting from maximal to sufficient perceptual contrast (Vallée, 1994; Schwartz et al., 1997). At the turn of the twenty-first century, the theory of complexity further pervaded the study of phonological systems. Shifting from variation-less inventories at a communal level to collections of speakers and individual inventories was one of the successful paths explored.