As languages evolve, they tend to lose irregular forms of words. Oddball past tenses of irregular verbs morph into the regular form. In English, that means forming the past tense by appending "ed" to the root word as in "finish/finished." Linguists suspect that the more frequently an irregular form is used within a language community, the more resistant it is to such evolutionary change.
Two research teams, working independently, have used extensive statistical analysis to show that resistance to change does indeed correlate with the frequency of a word's usage. In fact, this seems to be a general rule governing the evolution of language.
You can see this rule at work in English today. "Forecast" is an irregular verb whose present and past tenses are the same - "forecast/forecast." It's used less frequently in spoken and written English than a high-usage irregular verb such as "say/said." But listen carefully to TV meteorologists and you'll hear some of them talking about what was "forecasted" yesterday. "Forecasted" is even showing up in some scientific papers. "Say/said" is here to stay. But "forecast/ forecast" is morphing into "forecast/forecasted."
Mathematician Erez Lieberman at Harvard University in Cambridge, Mass., and colleagues have studied the emergence of this rule in English over the past 1,200 years. They explained last month in Nature how they have tracked inflectional changes to 177 irregular verbs in Old-English (Beowulf's English) through Middle English (Chaucer's English) to Modern English.
By Chaucer's time, 145 of those old irregular forms remained and 98 of them are still with us today. (English speakers today might enjoy knowing that they are using some of the same irregular verbs that Beowulf and Chaucer spoke.)
Yet the rule that less-used irregular forms evolve into regular forms faster than much-used forms stands out in their analysis. …