This paper aims to explain possessive noun phrases with double possessor reference in Spanish: su casa de Juan. The usual explanation for the possessive duplications in Spanish has been based on a way of mitigating reference ambiguity of the pronoun su(s) which is a unique form that covers different numbers, persons and genders of possessors. This construction was present in Medieval Spanish but was lost in modern Peninsular Spanish except very limited use like su casa de usted(es). However it has remained alive in some American Spanish dialects. Nowadays it is spreading not only into modern Mexican-Andean Spanish but also into modern Peninsular Spanish. In American Spanish language contact might have taken place between Spanish and Indigenous Languages like Nahuatl or Quechua. In this study I verify the transference of corresponding structures of Indigenous Languages in American Spanish. I intend to describe unique and distinctive aspects of possessive duplications among Medieval Spanish, Mexican Spanish and Andean Spanish in detail as a result of the contrastive study and give a plausible explanation for each case from the cognitive perspective.