Duolingo, Inc. is a language-learning website and mobile application, which engages in the development of a free language learning website and crowd sourced text translation platform. The company is headquartered in Pittsburgh, Pennsylvania and currently employs 650 full-time employees. The company went IPO on 2021-07-28. The firm's flagship application, Duolingo, is a language learning application. The Duolingo language learning application is a way to learn languages. The firm offers courses in approximately 40 languages to more than 60 million monthly active users. The application is also available in the education category on both Google Play and the Apple App Store. Duolingo can also be accessed by desktop computers via a Web browser at www.duolingo.com. All course content on Duolingo can be accessed for free. Its subscription offering, Super Duolingo, offers learners additional features to enhance their learning experience. The company also launched a family plan, which includes up to six subscribers under one annual plan. The Duolingo English Test is an online English proficiency assessment. Anyone with a computer, webcam and Internet connection can take the test from anywhere, at any time.