Biologist Mark Pagel shares an intriguing theory about why humans evolved our complex system of language. He suggests that language is a piece of "social technology" that allowed early human tribes to access a powerful new tool: cooperation.
Jay Walker explains why two billion people around the world are trying to learn English. He shares photos and spine-tingling audio of Chinese students rehearsing English -- "the world's second language" -- by the thousands.
In her talk, longtime English teacher Patricia Ryan asks a provocative question: Is the world's focus on English preventing the spread of great ideas in other languages?