Evolving language compositionality in a frequency-structured meaning space

2026-07-31

AI Summary

This study investigates how the frequency distribution of meanings influences the evolution of linguistic compositionality, with a focus on whether high-frequency meanings can bypass grammatical constraints and how this affects intergenerational transmission. Using an iterated learning paradigm, the authors simulate the generational evolution of artificial languages within a meaning space endowed with controlled frequency structures, complemented by formal measures of compositionality. They find that compositionality is enhanced and stably transmitted across generations only when high frequency applies to holistic form–meaning units; in contrast, high-frequency subunits impede generalization and ultimately lead to system collapse. These findings underscore the critical role of holistic acquisition mechanisms in language evolution and offer a theoretical account for the irregularity commonly observed in high-frequency expressions in natural languages.

Abstract

The iterated learning model was introduced to investigate language evolution: the way in which the characteristic properties of human languages have been shaped, at least partly, by repeated transmission from one language user to another. The key finding is that language compositionality can arise spontaneously as a consequence of language being passed repeatedly through a language learning bottleneck. Here we explore how changing the frequency of different meanings, so that some meanings occur much more frequently than others, affects the character of its compositionality. We find that, as observed in natural languages, high-frequency meanings can escape the pressure to conform to the grammar that characterizes lower-frequency meanings. However, when the frequency structure is instead imposed on parts rather than on whole meaning vectors, the language fails to transmit across generations. This occurs despite the fact that the most frequent elements are reliably learned. These results suggest that frequency can shape emergent linguistic structure only when the frequency distribution is defined over form-meaning units that learners can acquire holistically. When frequency is instead distributed over smaller units, it fails to support the relational structure required for compositional generalisation, thereby preventing stable language transmission.

Problem

• compositionality
• language evolution
• frequency distribution
• iterated learning
• meaning space

Innovation

• iterated learning
• compositionality
• frequency structure
• language evolution
• holistic learning