During his travels in South America at the close of the 18th century, the German explorer Alexander von Humboldt came upon a parrot speaking the words of a lost Indian tribe. The encounter inspired our guest, acclaimed author and New York Times Magazine writer Charles Siebert, to imagine the echoes of human language that might persist, in nonhuman voices, once we are gone. We speak with Siebert about his reporting on humans’ wonder for and wounding of animals, the reach of metaphor, and what he discovered in the gaze of a chimpanzee named Roger.