Evolution of language

Nature has two papers on language which I'll pass along (I don't know enough about this area to say anything non-tardish) for those who have an interest in such things.

First, our old friend Martin Nowak is behind a group which published an article titled Quantifying the evolutionary dynamics of language:

...Here we describe the emergence of this linguistic rule amidst the evolutionary decay of its exceptions, known to us as irregular verbs. We have generated a data set of verbs whose conjugations have been evolving for more than a millennium, tracking inflectional changes to 177 Old-English irregular verbs. Of these irregular verbs, 145 remained irregular in Middle English and 98 are still irregular today. We study how the rate of regularization depends on the frequency of word usage. The half-life of an irregular verb scales as the square root of its usage frequency: a verb that is 100 times less frequent regularizes 10 times as fast. Our study provides a quantitative analysis of the regularization process by which ancestral forms gradually yield to an emerging linguistic rule.

Also, Frequency of word-use predicts rates of lexical evolution throughout Indo-European history:

...Across all 200 meanings, frequently used words evolve at slower rates and infrequently used words evolve more rapidly. This relationship holds separately and identically across parts of speech for each of the four language corpora, and accounts for approximately 50% of the variation in historical rates of lexical replacement. We propose that the frequency with which specific words are used in everyday language exerts a general and law-like influence on their rates of evolution. Our findings are consistent with social models of word change that emphasize the role of selection, and suggest that owing to the ways that humans use language, some words will evolve slowly and others rapidly across all languages.

I hope Language Hat or Language Log see this at some point....


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The abstracts pretty much say it all. As they mention, it's been known that less frequent forms (not just verbs but nouns too -- like "oxen") die off more quickly. What they did was make it into an exponential decay model and see what the observed parameter values are.

You'd think someone would've done that by now, but linguists, especially the historical ones, don't use much math. Those who do almost never use numbers. The neural network people probably know the most number-based math, but they don't look at historical change and hate the idea of rules to begin with!

Notice that none of the authors of either paper belong to a department of linguistics -- either math or more math-driven biology. This will be a common occurrence as math and physics niches becomes fully saturated with creative brainiacs. If you want a quick Nature paper, why not colonize some defenseless area like historical linguistics? They don't stand a chance, and you're free to exploit the cleansed landscape.

As a linguist, I totally agree that my field has largely ignored the revolution in scientific thinking that mathematical models have provided other fields. It is the computational linguists and statisticians who have brought mathematical modeling into linguistics. I think language evolution is one of those areas that stands to make tremendous gains from mathematical models. Look at the work of Partha Niyogi's and you'll see the future of historical linguistics.