Across the Curious Parallel of Language and Species Evolution

Abstract

In February 1837—even before he sailed on the Beagle—Charles Darwin wrote to his sister Caroline, discussing the linguist Sir John Herschel's idea that modern languages were descended from a common ancestor. If this were really the case, it cast doubt on the Biblical chronology of the world: “[E]veryone has yet thought that the six thousand odd years has been the right period but Sir J. thinks that a far greater number must have passed since the Chinese [and] the Caucasian languages separated from one stock” [1]. The example of language change was a lifelong influence on Darwin's thought (see Figure 1). In The Origin of Species, he argued that our ability to order languages genealogically, despite their having changed and divided at different rates, shows that the same can be done for species [2]. And in The Descent of Man, he noted that: “The formation of different languages and of distinct species, and the proofs that both have been developed through a gradual process, are curiously parallel” [3]. Figure 1 Language and Darwin The tools of evolutionary analysis now allow both biologists and linguists to investigate whether these parallel paths might actually intersect, or perhaps be lanes of the same highway. And by giving the study of language change a quantitative edge, this approach has revealed striking similarities between the dynamics of biological evolution and language change. “Languages are extraordinarily like genomes,” says evolutionary biologist Mark Pagel of the University of Reading, UK. “We think there could be very general laws of lexical evolution to rival those of genetic evolution.” What form this law might take is up for grabs; a particular mystery is how the regular changes that become apparent over centuries and millennia relate to the myriad processes that influence how individuals learn and use language. Evolutionary ideas are making their presence felt here, too, although the relative contribution of biological and cultural evolution, and how they might interact, is disputed. But it's possible, say some, that an understanding of how language changes could form part of a general theory encompassing both biological and cultural evolution. “If there's a model system for cultural evolution, then probably the people working on language have got it, because there's so much data,” says psychologist Alex Mesoudi of Cambridge University.