Editor's Summary
11 October 2007
Words on the brink
As a language evolves, grammatical rules emerge and exceptions die out. Lieberman et al. have calculated the rate at which a language grows more regular, based on 1,200 years of English usage. Of 177 irregular verbs, 79 became regular in the last millennium. And the trend follows a simple rule: a verb's half-life scales as the square root of its frequency. Irregular verbs that are 100 times as rare regularize 10 times faster. The emergence of a rule (such as adding –ed for the past tense) spells death for exceptional forms. The cover graphic makes the point: verb size corresponds to usage frequency, so large verbs stay at the top, and small verbs fall to the bottom. 'Wed', the next irregular verb to go, is on the brink. In a separate study, Pagel et al. looked at changing word meanings. Across the Indo-European languages, words like 'tail' or 'bird' evolve rapidly and are expressed by many unrelated words. Others, like 'two', are expressed by closely related word forms across the whole language family. Data from over 80 modern languages show that the more a word is used, the less it changes.
News and Views: Linguistics: An invisible hand
Quantitative relationships between how frequently a word is used and how rapidly it changes over time raise intriguing questions about the way individual behaviours determine large-scale linguistic and cultural change.
W. Tecumseh Fitch
doi:10.1038/449665a
Letter: Quantifying the evolutionary dynamics of language
Erez Lieberman, Jean-Baptiste Michel, Joe Jackson, Tina Tang & Martin A. Nowak
doi:10.1038/nature06137
First paragraph | Full Text | PDF (461K) | Supplementary information
Letter: Frequency of word-use predicts rates of lexical evolution throughout Indo-European history
Mark Pagel, Quentin D. Atkinson & Andrew Meade
doi:10.1038/nature06176
First paragraph | Full Text | PDF (282K) | Supplementary information
