Proto-language

Proto-language may refer to either:

1. a language that is the common ancestor of a set of related languages (a language family), or
2. a system of communication during a stage in glottogony that may not yet be properly called a language.

Languages inferred from other languages

A proto-language is a language which was the common ancestor of related languages that form a language family. The German term Ursprache (derived from the prefix Ur- "primordial" and Sprache "language") is occasionally used as well.

In most cases, the ancestral proto-language is not known directly and it has to be reconstructed by comparing different members of the language family via a technique called the comparative method. Through this process only a part of the proto-language's structure and vocabulary can be reconstructed; the reconstruction remains the more fragmentary the more ancient the proto-language in question is. Examples of unattested but (partially) reconstructed proto-languages include Proto-Indo-European, Proto-Uralic and Proto-Bantu – the ancestors of Indo-European, Uralic and Bantu languages, respectively. Sometimes, however, the proto-language is a language which is known from inscriptions, an example being the Proto-Norse language attested in the Elder Futhark runic inscriptions.

A communication mode less complete than true language

An absolute proto-language, as defined by linguist Derek Bickerton, is a primitive form of communication lacking:

• a fully-developed syntax
• tense, aspect, auxiliary verbs, etc.
• a closed (i.e. non-lexical) vocabulary

The "me Tarzan, you Jane" nature of proto-language in this last sense is evident in pidgins, some features of early childhood language, and the language of adults who were deprived of language during the critical period (such as the feral child Genie). Derek Bickerton suggests language evolved from this kind of proto-language in a linguistic 'big bang'. But see also Terrence Deacon's arguments in his book The Symbolic Species for a radically different point of view.