Joseph Greenberg, in his highly contested theory of the Amerind superfamily, places the Quechua language family in the Andean branch of Amerind, which is part of the larger Southern Amerind branch that encompasses all indigenous South American languages. Much of Greenberg's proposal has been disproved, and his claims regarding Quechua are equally suspect. Even at one of his lower subgroupings, the Andean language family, the idea that Andean languages such as Quechua and Aymara are related is still debated, and the common consensus is that similarities between Quechua and Aymara arose from language contact as opposed to a genetic relationship.