Contrary to what is suggested in the literature, "certain" when it modifies the proper noun, breaks up sharply of denominative predicates like dénommé or appelé, by morphosyntactic and semantic features. Besides, the syntactic modification which "certain" operates does not concern to the réfèrent but to its mode of donation which depends on the sub-categorization of Npr according to the ontology of the referents (persons vs place) and according to their membership in public vs private spheres. In this respect, "certain" seems specialized in the modification of familial Npr whose referent has "double face": at the same moment indefinite ie totally unknown of the addressee and specifie ie wellknown for the speaker via his experiment or media.