family-tree theory

American  

[fam-uh-lee tree, fam-lee-] / ˈfæm ə li ˈtri, ˈfæm li- /

noun

Historical Linguistics.

1. a theory that describes language change in terms of genetically related languages developing in successive splits from a common parent language, such as Indo-European, as depicted by a family tree diagram.

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Etymology

Origin of family-tree theory

First recorded in 1930–35