This dissertation analyzes the morpho-syntactic, semantic, and pragmatic-discourse properties of Spanish dative and accusative clitic pronouns in clitic doubling constructions (CD), in which the clitic co-occur with the constituent it agrees with. Some limitations from previous studies arise from the type of motivations argued regarding the realization of CDs, which have usually ignored or granted a secondary role to the argument status of doubled objects, and, more importantly, to their discursive function and their role as participants in the event structure. This study examines previous proposals and includes their findings within the frame of linguistic evolution and typology based on the grammaticalization process that pronominal clitics underwent. Specifically, Cuervo’s (2003) analysis of doubled dative arguments is extended to accusative contexts, and I offer several arguments that support the understanding of non-pronominal accusative CDs as a discursive strategy formally licensed by the clitic. Following Belloro (2007), the semantic input of clitics in CD would be that of “cognitive accessibility”, which establishes the discursive status of doubled objects both in dative and accusative contexts. Thus, accusative clitics are considered functional elements that act as applicative heads in doubling constructions of non-pronominal nominal phrases. In Cuervo’s terms, Accusative Applicative Constructions have a structural meaning since it is determined by the type of “object” the head selects as its complement, and what constituent the applicative phrase complements. This analysis is formalized under the principles of Distributed Morphology framework. Particularly, “feature under specification” and the distribution of morpho-syntactic features are argued to be the optimal mechanisms to account for the variation and optional/obligatory realization of CDs. This formal representation also accounts for the relationship between different levels of formal representations and different levels of meaning.