Luis von Ahn is a Guatemalan entrepreneur and an associate professor in the Computer Science Department at Carnegie Mellon University. He founded reCAPTCHA, which was sold to Google in 2009, and then co-founded Duolingo, world's largest language-learning online platform. Duolingo was started as a project in Pittsburgh by von Ahn and his graduate student, Severin Hacker. Duolingo's effectiveness is due to its use of machine-learning algorithms that understand users' learning patterns to create personalized lessons, as well as rigorous big data analysis of its millions of users. It's free, with no ads. The service was designed to feel like a game that makes it effective — an independent study by City University of New York has shown that 34 hours on Duolingo are equivalent to a university semester of language classes. Verizon is offering the Pixel 4a for just $10/mo on new Unlimited lines

I met Luis some time ago when he travelled to India, and talked about Duolingo's success and partnerships, the next set of goals, and why India is the market the company was focusing on right now. To coincide with the visit, the company announced the launch of the app in Hindi with a customized experience for Hindi speakers. By the numbers Duolingo has a total of 110 million users across the world. About 60 percent of Duolingo users use it for learning English. In India, Duolingo has had a million app downloads with over 200,000 monthly active users. The growth is staggering since the number was 150,000 a month ago. Partnerships Duolingo is used for language education in many schools in United States. Five percent of all public schools in the U.S. use Duolingo to teach languages. We've also partnered with the government of Columbia, Mexico, and a few other countries. The UK, too. We definitely want to partner with some schools in India. It makes a lot of sense to partner with schools in rural areas, where the school teacher also doesn't speak English well, and they can use Duolingo to teach English. It helps getting students excited about learning because it's a game. It is also personalized for an individual... so the content, speed, and style is tailored for an individual. Focus on India The latest version of the app is tailored for the Indian market. In most countries, we just launch the app. We don't bother in looking in how the people are using it. But India is a big enough market and we decide to look into its usage and patterns. So, India is the first market we've ever customized Duolingo for. We've never had a dedicated team at Duolingo for a specific market. Now we are doing things that are very particular of how people use the app in India One of the stupid assumptions we made was that you don't need to learn English if your phone's language is English. In India, a lot of people have their phone set to English, but they don't know English well. We made the incorrect assumption, and didn't show English as a language to be learned. This has changed now. Also, typing in Hindi is rare. People prefer not to type in Hindi, and in fact they prefer to type Hindi in Roman letters. We've removed the need to type in Hindi in the app. We're also working really hard to make the bandwidth usage a lot smaller. We've drastically reduced the size of the app. The Android app, for example, used to be 20 MB, and it is now about 7MB. We're trying to reduce it even more. We realized that a lot of people don't have a lot of space on their phones. We are trying to reach phones with low memory, while consuming less bandwidth.