Size matters in language evolution – experts respond

When it comes to new words, size matters. An Australian-based study of 20 Polynesian languages, including New Zealand Maori, suggests that widely-spoken languages gain new words more frequently while those with just a few speakers tend to lose words faster.

How the size of a population affects the evolution of language is unclear. Do languages with larger speaker populations change faster due to a greater capacity for innovation, or do smaller populations change faster because new words spread throughout them quickly?

To tackle this questions, researchers from the Australian National University analysed historical and modern language data from 20 Polynesian languages from countries across the Pacific, ranging from Papua New Guinea to Rarotonga. They found that rates of gain of new words are higher in larger populations whereas rates of word loss are greater in small populations. The research is published today in PNAS.

“What we found is that languages with bigger populations of speakers are much more open to innovation,” said lead author Dr Simon Greenhill, from the Centre of Excellence for the Dynamics of Language.

“The results suggest that population density encourages innovation, and those innovations spread through the community – in other words having more speakers generates a churn effect, speeding up the rate of language change.”

The SMC collected the following expert commentary. Feel free to use these quotes in your reporting. If you would like to contact a New Zealand expert, please contact the SMC (04 499 5476; smc@sciencemediacentre.co.nz).

Assoc. Prof. Quentin Atkinson, Rutherford Discovery Fellow, School of Psychology University of Auckland, comments:

“This is part of a revolution in linguistics, using computational tools from evolutionary biology to understand how languages evolve. Computer models allow us to identify general laws of language change just as they do in biology. Biologists know that population size affects the rate at which new genetic mutations appear in populations (more mutations occur in bigger populations) and the probability that variants are lost (more variants are lost in smaller populations).”This paper uses the Pacific as a unique natural experiment to test a similar idea in linguistics –  that population size might affect how quickly new words are gained and lost. By comparing language change on islands with different population sizes, they find is that population size does indeed affect rates of gain and loss as predicted.

“The case of New Zaland Maori is tricky, because whilst the pre-European contact Maori population was very large (the largest of all the Pacific languages considered in the study), the Maori speaking population declined steeply post-contact. So it is more difficult to make clear predictions about Maori. Nevertheless, it is interesting that the study finds a relatively high rate of word gain and word loss in Maori – a high word turnover – when compared to its close relatives.”