The half-life of words

This year marks the 100th anniversary of the term “half life,” which is used in disciplines ranging from the physics of radioactive decay to chemistry to biology. But the half life of a word?

Harvard Professor Martin Nowak and fellow researchers observed that every single one of the ten most common verbs in English: be, have, do, go, say, can, will, see, take, and get, is irregular. Because they’re so common they are less likely to change over time and so they stay irregular.

Then the researchers quantified the relationship between a verb’s frequency of use and its longevity as follows: “The half-life of an irregular verb scales as the square root of its usage frequency.”

This means that irregular verbs not commonly used become regular over time.

In other words, an irregular verb that is 100 times less frequent regularizes 10 times as fast because 10 is the square root of 100.

Here’s one example: Chaucer used the irregular form of holp for the past tense of help; today only the regular form helped survives.

And that’s no Canterbury Tale.