On the emergence of syntactic structures: quantifying and modelling duality of patterning

TL;DR

This paper introduces measures to quantify duality of patterning in language, develops a framework for empirical estimation, and demonstrates how cultural dynamics can lead to the emergence of hierarchical syntactic structures.

Contribution

It provides a novel quantitative framework and empirical methods to analyze the emergence of syntactic duality through multi-agent modeling and language games.

Findings

Theoretical predictions align with empirical data.

Duality of patterning emerges from cultural dynamics.

Simple constraints can induce hierarchical structures.

Abstract

The complex organization of syntax in hierarchical structures is one of the core design features of human language. Duality of patterning refers for instance to the organization of the meaningful elements in a language at two distinct levels: a combinatorial level where meaningless forms are combined into meaningful forms and a compositional level where meaningful forms are composed into larger lexical units. The question remains wide open regarding how such a structure could have emerged. Furthermore a clear mathematical framework to quantify this phenomenon is still lacking. The aim of this paper is that of addressing these two aspects in a self-consistent way. First, we introduce suitable measures to quantify the level of combinatoriality and compositionality in a language, and present a framework to estimate these observables in human natural languages. Second, we show that the theoretical predictions of a multi-agents modeling scheme, namely the Blending Game, are in surprisingly good agreement with empirical data. In the Blending Game a population of individuals plays language games aiming at success in communication. It is remarkable that the two sides of duality of patterning emerge simultaneously as a consequence of a pure cultural dynamics in a simulated environment that contains meaningful relations, provided a simple constraint on message transmission fidelity is also considered.