Like a skyscraper skeleton that goes up overnight–but doesn’t get windows for another decade–languages evolve in fits and starts, according to a new study. The idea that languages evolve in bursts, rather than gradually, isn’t new. When applied to species, it’s called punctuated evolution. But the idea is controversial in both fields–and proof has been hard to come by. Now, scientists in the United Kingdom say they’ve mustered the power of mathematics to demonstrate the phenomenon in the evolution of languages. The researchers, headed by evolutionary biologist Quentin Atkinson and mathematician Mark Pagel of the University of Reading, looked at related versions, or homologs, of common words in three of the world’s major language families: Indo-European, Bantu, and Austronesian. Like species, changes in languages can be tracked through the fate of certain words, just as mutations in key genes can tell a species’ history.
The words the researchers tracked are from the so-called Swadesh lists: compilations of heavily used words denoting things such as numbers or body parts that change little over time and are rarely borrowed, making them good clues about how one language relates to another. An example from the Indo-European language family is the words for “water” in English, German (“Wasser”), Hittite (“watar”), and Russian (“voda”). Despite many borrowings, English is much further from Latin languages such as French, according to the Swadesh lists. Consider, for example, the French for water–“eau.”