Proto-language

In the tree model of historical linguistics, a proto-language is a postulated ancestral language from which a number of attested languages are believed to have descended by evolution, forming a language family. Proto-languages are usually unattested, or partially attested at best. They are reconstructed by way of the comparative method. In the family tree metaphor, a proto-language can be called a mother language. Occasionally, the German term Ursprache (pronounced [ˈuːɐ̯ʃpʁaːxə] ; from ur- 'primordial, original' + Sprache 'language') is used instead. It is also sometimes called the common or primitive form of a language (e.g. Common Germanic, Primitive Norse). In the strict sense, a proto-language is the most recent common ancestor of a language family, immediately before the family started to diverge into the attested daughter languages. It is therefore equivalent with the ancestral language or parental language of a language family. Moreover, a group of lects that are not considered separate languages, such as the members of a dialect cluster, may also be described as descending from a unitary proto-language.