Glottochronology's an approach in historical linguistics for estimating the time at which languages diverged, based on the assumption that the basic (core) vocabulary of a language changes at a constant average rate. This assumption, originally suggested by Morris Swadesh,'s based on an analogy with the use of carbon dating for measuring the age of organic materials, in that a "lexical half-life"'s estimated. The method estimates the length of time since two or more languages diverged from a com… (More on Glottochronology)