Are bilingual signposts that we have seen sprouting for some time at Breton roadsides and in Breton towns translation ? If one examines what translation is, not only can it be considered translation, but bilingual signs are indeed the object of a translation service formally made up of a work provider, a service provider and a readership. The exchange between these roles presents however distinctive features related to the languages in question. One does not translate nowadays into regional languages to enable people that could not otherwise understand each other to communicate. The negotiation taking place by this means therefore answers to other motivations of both the work and the service providers that should be analysed. The Mediation theory provides interesting keys to understanding the observed social relations.