There are more than 7,000 languages spoken on Earth, but by the end of the century, 30% of these could be lost. This week, research warns that knowledge of medicinal plants is at risk of disappearing as human languages become extinct. Phoebe Weston speaks to Rodrigo Cámara Leret about the study, and the links between biological and cultural diversity. Help support our independent journalism at <a href="https://www.theguardian.com/sciencepod">theguardian.com/sciencepod</a>