手法を比較

	Glottochronology (Lexical Dating)	比較言語学的方法
分野	言語学	言語学
系統	Process / pipeline	Process / pipeline
提唱年	1952	1786
提唱者	Morris Swadesh	Sir William Jones
種類	Estimation of time depth of language separation from cognate retention	Empirical process pipeline
原典	Swadesh, M. (1955). Towards greater accuracy in lexicostatistic dating. International Journal of American Linguistics, 21(2), 121–137.	Hock, H. H. (1991). Principles of Historical Linguistics (2nd ed.). Berlin: Mouton de Gruyter.
別名	Glottochronology, Lexicostatistic Dating, Linguistic Dating	Historical Comparative Linguistics, Genetic Linguistics
関連	4	4
概要	Glottochronology is Morris Swadesh's method for estimating the time depth at which two related languages separated, derived from the proportion of basic-vocabulary cognates they still share. Building directly on lexicostatistics, it adds a crucial extra assumption — a 'glottoclock' — that basic vocabulary is lost at an approximately constant rate over time, analogous to radioactive decay. Plugging the observed cognate proportion into a logarithmic decay formula yields an estimated separation date in years. The method is historically important but has been heavily criticized, and most historical linguists today treat its dates with great caution.	The Comparative Method is a foundational technique in historical linguistics for reconstructing ancestral languages and establishing genetic relationships between related languages. Pioneered by Sir William Jones in 1786, it systematically compares phonological, morphological, and lexical features across languages to identify regular sound correspondences and trace their shared origins. This method underpins modern historical linguistics and has been essential for understanding language families worldwide.