The Vasconic substrate hypothesis is a proposal that several Western European languages contain remnants of an old language family of Vasconic languages, of which Basque is the only surviving member. The proposal was made by the German linguist Theo Vennemann, but has been rejected by other linguists.
According to Vennemann, Vasconic languages were once widespread on the European continent before they were mostly replaced by Indo-European languages. Relics of these languages include toponyms across Central and Western Europe.
Theo Vennemann (2003) proposes that after the last Ice Age, Vasconic people (perhaps coming from Africa) resettled all of Western Europe. They gave names to the rivers and places. These names often persisted after the Vasconic languages were replaced by Indo-European languages in most of their area. The present Basque area in northern Spain and southern France is postulated to be a relic.
In support of this argument, Vennemann cites, inter alia:
Vennemann developed his ideas in a series of papers which were collected in a book called Europa Vasconica - Europa Semitica. A long critical review of this appeared in Lingua 116.
The hypothesis has been largely rejected by historical linguists. Vennemann's theories on "Vasconic" toponymy and hydronymy were opposed by linguists such as P. R. Kitson (1996), and Baldi & Richard (2006), who pointed out that most linguists see unusual European hydronyms as more likely to have Indo-European roots of some kind. German linguist Dieter H. Steinbauer argued that it is difficult to argue on the basis of Basque because:
Steinbauer also criticised Vennemann for
Abstract: In this review article we evaluate Theo Vennemann's provocative theories on the role of Afroasiatic and Vasconic (e.g. Basque) languages in the pre-historic development of Indo-European languages in Europe as presented in the volume Europa Vasconica-Europa Semitica, a collection of 27 of Vennemann's essays...