Glottochronology refers to methods in historical linguistics used to estimate 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 put forward by Morris Swadesh, is based on an analogy with the use of carbon dating for measuring the age of organic materials, in that a "lexical half-life" is estimated. The method estimates the length of time since two or more languages diverged… (More on Glottochronology)