All the Apiaca speak Portuguese and those married to members of the Munduruku and Kaiabi tribes speak their spouse’s language fluently or have the ability to understand them fully. Although the Munduruku and Kaiabi languages and idioms are spoken on a day-to-day basis in the Apiaca villages, they are, however, limited to domestic spaces and informal conversations. The language used in formal conversations is Portuguese, due to contact with the Neo-Brazilians and Portuguese settlers. Although they cannot impose their own language on the co-resident Munduruku and Kaiabi people, due to such a small number of them who actually speak the Apiaca language, the Apiaca manage to impede the languages of these peoples from becoming the official languages in their villages. This allows Portuguese to function as an instrument of resistance employed by the Apiaca to prevent their cultural absorption by the Munduruku and Kaiabi tribes.