1. protolanguage; parent languageLinguistics
Wikipedia definition
2. Proto-languageA proto-language (alternatively known as a parent language, or common ancestor) in the tree model of historical linguistics is a hypothetical, or reconstructed, typically extinct language from which a number of attested, or documented, known languages are believed to have descended by evolution, or slow modification of the proto-language into languages that form a language family. Occasionally, the German term Ursprache is used instead.
Read “Proto-language” on English Wikipedia
Read “祖語” on Japanese Wikipedia
Read “Proto-language” on DBpedia


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