When a colleague’s tip led José Antonio Mazzotti, the King Felipe VI of Spain Professor of Spanish Culture and Civilization at Tufts, to a remote village in central Peru, most scholars believed that the ancient, undocumented language known as Iskonawa was nearly extinct, spoken only by a handful of people living in voluntary isolation on that country’s border with Brazil. Then Mazzotti met a village elder named Doña Nelita and heard her story.