In this episode of ACM ByteCast, Rashmi Mohan hosts past ACM Grace Murray Hopper Award recipient Luis von Ahn, co-founder and CEO of Duolingo, the world's most popular language-learning platform. He is also a Consulting Professor in the Computer Science Department at Carnegie Mellon University. Known as one of the pioneers of crowdsourcing, his many recognitions include the MacArthur Fellowship, MIT Technology Review's TR35, and the Lemelson-MIT Prize.

They discuss how he, Manuel Blum, and others at Carnegie Mellon conceived the now famous technology behind reCAPTCHA, the company he founded before Duolingo, and sold to Google in 2009. Von Ahn gives insight into his journey toward harnessing the power of crowdsourcing to provide free, globally distributed language learning. They discuss the dominance of the English language in computing, the benefits and challenges of starting a company in Pittsburgh, some Duolingo user stories Luis has found particularly gratifying, and more.