This paper is an extensively revised and expanded version of the first part of a broader paper that was circulated as Ormazabal & Romero (2002) and also included a syntactic analysis of the agreement restrictions discussed here. The syntactic proposal analyzed the properties of a series of ditransitive constructions that were shown to be subject to the restriction: dative Constructions, dative Clitic Constructions and Double Object Constructions, all in a broad variety of languages. Due to editorial requirements, we have extended the descriptive sections of the work, leaving the more theoreticallyoriented parts of our proposal for a forthcoming paper.