Duolingo

Duolingo is the leading mobile learning platform globally and offers free and subscription access to one hundred courses teaching forty languages, such as Spanish, Japanese, German, Arabic, Hindi, and Korean. Duolingo is available as iOS and Android mobile apps and online via web browsers.

Duolingo's flagship app has had over 500 million downloads, and the company has over 40 million monthly active learners completing 500 million exercises per day. Duolingo is the top-grossing app in the education category on both Google Play and the Apple App Store, is the most downloaded education app in the history of the App Store, and has been awarded Apple's iPhone App of the Year and Android's Best of the Best.

The story behind Duolingo's mission - Luis von Ahn, CEO (2017)

Duolingo had its IPO on June 28, 2021, and is publicly traded on the Nasdaq exchange under the symbol DUOL. Duolingo has been named to Forbes' "Next Billion Dollar Startups" (2019), CNBC's Disruptor 50 (2018, 2019), Fortune's "Change the World" list (2019), TIME Magazine's Genius Companies (2018), Fast Company's "Most Innovative Companies" (2017, 2018, 2020), Inc.'s "Best Places to Work" (2018), and Entrepreneur's "Top Company Cultures" (2018).

Duolingo offers free and subscription versions of its language learning app. The Super Duolingo subscription is $6.67 per month, which is ad-free, allows users to enable unlimited "hearts" and review mistakes, and has unlimited test-outs. Families can also subscribe up to six members under a Super Family Duolingo account for $10/month.

The company also offers Duolingo ABC, a free English literacy app for children ages three to six; Duolingo for Schools, which allows teachers to track their students; and the Duolingo English Test, a convenient, fast, and affordable English test accepted worldwide.

In 2023, Duolingo announced the introduction of a new "Max" subscription tier, which included features powered by OpenAI's GPT-4 technology. These new features, powered by artificial intelligence, are called "Roleplay" and "Explain My Answer." These features were initially available for English speakers learning French or Spanish, and for the Australia, Canada, Ireland, New Zealand, United Kingdom, and United States regions, with plans to continue to expand the service.

The Roleplay feature offers an AI chatbot that allows users to practice real-world conversation skills through the app. The AI is developed to be both responsive and interactive, capable of guiding users through different scenarios. And it offers users feedback on the accuracy and complexity of their responses with tips for future conversations. The Roleplay prompts are written by human experts to ensure that the prompt and resulting scenario are aligned with where the user is in their learning and experience. These experts are also responsible for writing the initial messages in the conversations and guiding the AI model on where to take the conversation.

The Explain My Answer feature is intended to give users a chance to learn more about their responses in a lesson, understand why their answers are right or wrong, and ask for further clarification and examples of correct answers. The feature is designed to help users learn from making a mistake, understand the mistake to lead them to the right answer in the future, and better understand the underlying language rules. This can better help users learn in the short- and long-term and understand the language they are learning better.

Duolingo was founded by Luis von Ahn and Severin Hacker in 2011 in Pittsburgh, Pennsylvania. Luis von Ahn was a professor at Carnegie Mellon University, and he had already sold two start-ups to Google. And Severin Hacker was one of his Ph.D. students. They built Duolingo on the concept that learning a language should not be expensive and should be fun. Many people learn a new language to improve their lives, and the founders wanted the ability to learn to be accessible to everyone around the world.