Punctuated Equilibrium drives Language Evolution

Fellow blogger, Simon Greenhill of HENRY, and co-authors published a cool paper evaluating language evolution that just came out in today’s issue of Science. The premise behind the paper, “Languages Evolve in Punctuational Bursts,” is simple to follow. By comparing related versions, or homologs, of common words between the following language families: Indo-European, Bantu, and Austronesian, changes in languages can be tracked through the fate of certain words, just as mutations in key genes can tell a species’ history.

The team selected the homologous words from a Swadesh list, one of several linguistic lists of vocabulary where the words have “basic.” Swadesh lists are used is used in lexicostatistics, a way of quantitative language relatedness assessment as well as glottochronology, a method to assess and date language divergence dating. Swadesh lists were used in this study because they are changed very little over time and are rarely borrowed, making them good clues about how one language relates to another.

In my own head, I’ve built my own set of Swadesh lists and compared them to languages I’ve come across. I wish I thought about making some sort of formal study out of my observations. I guess Simon et al. beat me to the punch! Here’s a couple of examples from a cross Indo-European language family comparison that I’ve conjured up…. The words for father and mother in English, Spanish padre and madre, Farsi (Persian) pedar and madar. Despite many borrowings, English the much younger languages is much phonetically different from Latin languages in this example, and even more derived from the Farsi homologs.

Using this sort of comparative vocabulary data, Simon et al. were able to construct phylogenetic trees to show how new languages sprouted from root languages. Furthermore, applying the same mathematical models that showed that biological speciation can occur in bursts, to language to conclude that lineages with many “nodes,” or offshoots, change faster over time than language families that have few offshoots. And most of this acceleration occurs right around time the new languages separated from their ancestral lines.

I love these sorts of comparisons, especially because punctuated equilibria is fresh on my mind. As recent as last week has there been an explosion of discussion on punctuated equilibrium on Sandwalk, the Loom and Greg Laden’s blog. But anyways, I must hand it to Simon Greenhill and his coauthors who gracefully integrated an evolutionary biological concept into a linguistic anthropological scope. It really doesn’t matter whether the replicators are genes or words, the same approaches can be used to analyze the data and explain the model.

One last thing, do read Simon’s blog post describing his project and involvement as well as the Nature News coverage on the paper.

    Atkinson, Q.D., Meade, A., Venditti, C., Greenhill, S.J., Pagel, M. (2008). Languages Evolve in Punctuational Bursts. Science, 319(5863), 588-588. DOI: 10.1126/science.1149683

4 thoughts on “Punctuated Equilibrium drives Language Evolution

  1. Ha!

    I’d actually told my students this in class earlier this week. I talked about punctuated equilibrium in relation to the Great Vowel Shift in English, but it’s good to see that I’m not completely pulling stuff out of thin air.

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