The startup that turned learning languages into a game is trying to disrupt a $5 billion industry

Of the 1.2 billion people on Earth attempting to learn foreign languages, 800 million have chosen to study English, and they are probably not doing it to binge-watch House of Cards or read the collected works of Sir Walter Scott. Learning English has become synonymous with economic advancement across the developing world. Research from the British Council suggests that just knowing the language equates to a 25 percent bump in earnings, and many fields, from tourism to academia, have become...