In order for us to produce the sounds that we produce that are languages across all humans, the larynx had to drop significantly in the throat and we're the only animal that has that. So what you can do is you can look at the fossil record and you can tell when this happened in humans. And that turns out to be plus or minus 100 something thousand years ago. But his idea is that it's spread like a virus. It just like hopped on the scene and it finds some place in the brain that isn't used that much and just spreads to everybody else. We don't have podcasts. Really the evolutionary pressure for podcasts is what explains all of this stuff.