Because education is such a broad area, I chose to focus on language learning.

If you get asked to do something that would take place down the road (say you get asked to speak at a conference that's a year away) and you wouldn't want to do it if it were taking place next week, then don't do it. This advice has helped me evaluate the opportunities that I truly want to dedicate my time to and those that I don't.

Every time you buy tickets on Ticketmaster, you help to digitize a book.

I finished reading High Output Management by Andrew Grove, which had such valuable insights for leaders that I've been forcing managers at Duolingo to read the book.

Together with my advisor, Manuel Blum, I co-invented CAPTCHAs, or computer-generated tests that humans are routinely able to pass but that computers have not mastered (they are the squiggly computer letters that are prevalent across the web).

I watch a lot of TV. That's how I spend most of my time outside of work. If I had more time, I would fill it 100 percent with watching TV.

The question that motivates my research is, if we can put a man on the Moon with 100,000 [people], what can we do with 100 million?