Still no evidence for an effect of the proportion of non-native speakers on language complexity -- A response to Kauhanen, Einhaus & Walkden (2023)

TL;DR

This paper defends previous findings that the proportion of non-native speakers does not influence language complexity, addressing critiques and clarifying methodological points in response to recent commentary.

Contribution

It provides a detailed rebuttal to critiques of prior work, reaffirming that language complexity is not significantly affected by L2 speaker proportions, and clarifies methodological issues.

Findings

Critiques of previous analysis are addressed and shown to be unsubstantiated.

Methodological clarifications support original conclusions.

Alternative analyses proposed by critics are critically evaluated and found lacking.

Abstract

In a recent paper published in the Journal of Language Evolution, Kauhanen, Einhaus & Walkden (https://doi.org/10.1093/jole/lzad005, KEW) challenge the results presented in one of my papers (Koplenig, Royal Society Open Science, 6, 181274 (2019), https://doi.org/10.1098/rsos.181274), in which I tried to show through a series of statistical analyses that large numbers of L2 (second language) speakers do not seem to affect the (grammatical or statistical) complexity of a language. To this end, I focus on the way in which the Ethnologue assesses language status: a language is characterised as vehicular if, in addition to being used by L1 (first language) speakers, it should also have a significant number of L2 users. KEW criticise both the use of vehicularity as a (binary) indicator of whether a language has a significant number of L2 users and the idea of imputing a zero proportion of L2 speakers to non-vehicular languages whenever a direct estimate of that proportion is unavailable. While I recognise the importance of post-publication commentary on published research, I show in this rejoinder that both points of criticism are explicitly mentioned and analysed in my paper. In addition, I also comment on other points raised by KEW and demonstrate that both alternative analyses offered by KEW do not stand up to closer scrutiny.