This paper explores how over three decades the language repertoires of the Arakmbut people of the southeast Peruvian Amazon have shifted from being mainly Harakmbut language based to Spanish language based. It queries not how one language has come to substitute another in the Arakmbut's daily lives, but what this shift means in terms of altering lifestyles, social relations, desirable affiliations and the altering value Harakmbut and Spanish language resources have for them in advancing these relationships.