 Besides Quechua and Aymara, he researched extinct languages such as Mochica and Puquina.The present classification of the Quechua language family is based fundamentally on his analysis and that of Gary Parker, who, independently, came to similar conclusions.He found that Quechua clearly did not originate, as is still often believed, in the region of the Inca capital Cuzco, but almost certainly somewhere considerably further north in Central Peru.