proto-

A prefix used in HISTORICAL LINGUISTICS to refer to a LINGUISTIC FORM or STATE of a LANGUAGE said to be the ancestor of ATTESTED forms/languages, e.g. Proto-Indo-European, Proto-Romance. More recently, some linguists have begun to use the term analogously in the context of language ACQUISITION, to refer to the emerging linguistic system of the young child, in such uses as ‘proto-conversation’, ‘proto-sentence’.