Here's an evolutionary talking point: Two new studies quantify parts of the mechanism by which frequently used words change slowly over many millennia whereas rarely used words more rapidly take on new forms.

In fact, frequency of word usage exerts a "lawlike" influence on the rapidity of language evolution, the research teams conclude in the Oct. 11 Nature. This discovery offers a new tool for retracing the history of major language families, reconstructing ancient tongues, and