For our final episode, Babel goes global. English is now spoken by about two billion people, more than a third of the world's population. As English expands in countries such as India, China and South Africa, regional varities are emerging. And it's not surprising. Most conversations in English nowadays occur between people who speak it as a second, third or fourth language. That's because there are four times as many non-native speakers in the world as native speakers, and they're developing their own standards and lexicons. Babel wraps up its summer series by asking: Who owns English, and why does it matter?