Sentence:  He has announced results on Hokan , Penutian , Uto-Aztecan , and almost all other American families and phyla , and has diagrammed their degree of interrelation ; but he has not worked out by <WSD>lexicostatistics</WSD> one comprehensively complete classification of even a single family other than Salish . 
Meaning of the word marked with <WSD> tags:  a statistical technique used in glottochronology; used to estimate how long ago different languages evolved from a common source language