noun
glottochronology
A technical term in historical linguistics for estimating the time depth of language divergence based on core vocabulary retention rates.
言語年代学は、基礎語彙の残存率から言語の分岐年代を推定する方法です。
Glottochronology is a method that estimates the divergence dates of languages from the retention rates of basic vocabulary.
Compound of 言語 (language), 年代 (age, era), and 学 (study). A calque of English 'glottochronology'.