The emergence of word-internal repetition through iterated learning: Explaining the mismatch between learning biases and language design

Abstract

The idea that natural language is shaped by biases in learning plays a key role in our understanding of how human language is structured, but its corollary that there should be a correspondence between typological generalisations and ease of acquisition is not always supported. For example, natural languages tend to avoid close repetitions of consonants within a word, but developmental evidence suggests that, if anything, words containing sound repetitions are more, not less, likely to be acquired than those without. In this study, we use word-internal repetition as a test case to provide a cultural evolutionary explanation of when and how learning biases impact on language design. Two artificial language experiments showed that adult speakers possess a bias for both consonant and vowel repetitions when learning novel words, but the effects of this bias were observable in language transmission only when there was a relatively high learning pressure on the lexicon. Based on these results, we argue that whether the design of a language reflects biases in learning depends on the relative strength of pressures from learnability and communication efficiency exerted on the linguistic system during cultural transmission.

The Transmission of Vowel Harmony and Vowel Disharmony: An Iterated Learning Study

“…First, it is possible that the asymmetry will occur after longer duration of language transmission, i.e., more generations in iterated learning studies. However, in many iterated learning studies with human participants, eight or fewer generations have been proved to reveal some features of transmission (experiments with five generations: Evjen, 2021;Motamedi et al, 2019Motamedi et al, , 2021Ota et al, 2021). Thus, it is not highly likely that no substantive bias effect in this study is due to short length of the chains.…”

“…Many languages tend to avoid repetition of consonants with some identical features (Gordon, 2016), but both consonant and vowel repetitions are preferred by learners in experiment context (Ota & Skarabela, 2016. In a followed-up experiment, Ota et al (2021) introduced interaction into the iterated learning paradigm. The results showed the increase of both forms of repetitions and more use of the vowel repetition.…”

From One Bilingual to the Next: An Iterated Learning Study on Language Evolution in Bilingual Societies

“…Such an increase in structure was accompanied by an increase in learnability. These results have since been replicated, suggesting that cultural transmission leads to the emergence of languages that are structured in a way that maximizes learnability and expressivity for a specific kind of linguistic environment (Beckner, Pierrehumbert, & Hay, 2017; Cornish, Smith, & Kirby, 2013; Kirby, Tamariz, Cornish, & Smith, 2015; Kirby & Tamariz, 2021; Motamedi, Smith, Schouwstra, Culbertson, & Kirby, 2021; Ota, San Jose, & Smith, 2021; Raviv & Arnon, 2018; Smith & Wonnacott, 2010).…”