(Reuters) -Language-learning app Duolingo Inc on Monday filed for a U.S. initial public offering and revealed that its revenue more than doubled in the first quarter this year. The company was last valued at $2.4 billion after a $35 million funding from Durable Capital Partners and General Atlantic in November. Duolingo recorded revenue of $55.4 million for the three months ended March 31. Net losses in the same period widened to $13.5 million from $2.2 million a year ago. The Pittsburgh-headquartered company, which expects to be listed on the Nasdaq, was founded in 2011 by two engineers, Luis von Ahn and Severin Hacker. The co-founders met at Carnegie Mellon University, where Luis was a professor in the computer science department and Severin was his Ph.D. student. Duolingo’s flagship app has more than 500 million downloads and is the top-grossing app in the education category on both Google Play and the Apple App Store, the company said in its prospectus. The company offers courses in 40 languages to about 40 million monthly active users. There are more people learning certain languages, such as Irish and Hawaiian, on the company’s platform than there are native speakers of those languages worldwide, it said in the filing. Goldman Sachs & Co as well as Allen & Company are the lead underwriters for the IPO. The company plans to start trading under the symbol “DUOL”. Reporting by Niket Nishant in Bengaluru; Editing by Devika Syamnath Our Standards: The Thomson Reuters Trust Principles.