duolingo

The idea of Duolingo was formulated in 2009 by Carnegie Mellon University professor Luis von Ahn and his Swiss-born post-graduate student Severin Hacker.{{cite news |url=https://techcrunch.com/2011/04/12/duolingo/ |work=TechCrunch |title=Meet Duolingo, Google's Next Acquisition Target; Learn A Language, Help The Web |first=M.G. |last=Siegler |date=2011-04-12 |access-date=2014-11-21 |archive-date=November 29, 2020 |archive-url=https://web.archive.org/web/20201129162336/https://techcrunch.com/2011/04/12/duolingo/ |url-status=live }}{{cite web |last=Loeb |first=Steven |date=2018-06-22 |title=When Duolingo was young: the early years |url=https://vator.tv/news/2018-06-22-when-duolingo-was-young-the-early-years |url-status=live |archive-url=https://web.archive.org/web/20180625024407/https://vator.tv/news/2018-06-22-when-duolingo-was-young-the-early-years |archive-date=June 25, 2018 |access-date=2019-12-21 |website=VatorNews}} Von Ahn had sold his second company, reCAPTCHA, to Google and, with Hacker, wanted to work on an education-related project.{{cite web |last=Ahn |first=Luis von |title=Luis Von Ahn's answer to What made Luis Von Ahn start Duolingo? |url=https://www.quora.com/What-made-Luis-Von-Ahn-start-Duolingo/answer/Luis-Von-Ahn |url-status=live |archive-url=https://web.archive.org/web/20240222194940/https://www.quora.com/What-made-Luis-Von-Ahn-start-Duolingo/answer/Luis-Von-Ahn |archive-date=February 22, 2024 |access-date=2021-05-14 |website= |via=Quora}} Von Ahn stated that he saw how expensive it was for people in his community in Guatemala to learn English. Hacker (co-founder and current CTO of Duolingo) believed that "free education will really change the world"{{cite web |last=Olson |first=Parmy |title=Crowdsourcing Capitalists: How Duolingo's Founders Offered Free Education To Millions |url=https://www.forbes.com/sites/parmyolson/2014/01/22/crowdsourcing-capitalists-how-duolingos-founders-offered-free-education-to-millions/ |url-status=live |archive-url=https://web.archive.org/web/20140127012240/https://www.forbes.com/sites/parmyolson/2014/01/22/crowdsourcing-capitalists-how-duolingos-founders-offered-free-education-to-millions/ |archive-date=January 27, 2014 |access-date=August 26, 2017 |work=Forbes}} and wanted to provide an accessible means for doing so. He was recognized by the National Inventors Hall of Fame for his contributions to language learning and technological development.{{Cite web |date=October 27, 2023 |title=Duolingo creator to be inducted into Inventors Hall of Fame |url=https://www.nbcnews.com/now/video/duolingo-creator-to-be-inducted-into-inventors-hall-of-fame-196504645525 |url-status=live |archive-url=https://web.archive.org/web/20231102231928/https://www.nbcnews.com/now/video/duolingo-creator-to-be-inducted-into-inventors-hall-of-fame-196504645525 |archive-date=November 2, 2023 |access-date=2023-11-02 |website=NBC News |format=Video}} The Duo mascot is a green owl because co-founder Severin Hacker hates the color green.{{Cite web |last=Lee |first=Dami |date=2018-12-13 |title=Duolingo redesigned its owl to guilt-trip you even harder |url=https://www.theverge.com/2018/12/13/18137843/duolingo-owl-redesign-language-learning-app |url-status=live |archive-url=https://web.archive.org/web/20240329050328/https://www.theverge.com/2018/12/13/18137843/duolingo-owl-redesign-language-learning-app |archive-date=March 29, 2024 |access-date=2024-06-06 |website=The Verge |language=en}}

The project was originally financed by von Ahn's MacArthur fellowship and a National Science Foundation grant.{{cite web |last=Ahn |first=Luis von |date=2017 |title=Online Education as a Vehicle for Human Computation |url=https://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1054630 |url-status=live |archive-url=https://web.archive.org/web/20160304110021/https://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1054630 |archive-date=March 4, 2016 |access-date=April 6, 2018 |publisher=U.S. National Science Foundation}}{{cite news |last1=Masson-Forsythe |first1=Heather |date=December 22, 2022 |title=NSF gave Duolingo its wings! |url=https://beta.nsf.gov/science-matters/nsf-gave-duolingo-its-wings |url-status=live |archive-url=https://web.archive.org/web/20230325173930/https://beta.nsf.gov/science-matters/nsf-gave-duolingo-its-wings |archive-date=March 25, 2023 |access-date=25 March 2023 |work=U.S. National Science Foundation |language=en}}{{cite magazine |last=Giles |first=Jim |date=January 11, 2012 |title=Learn a language, translate the web |url=https://www.newscientist.com/article/mg21328476.200-learn-a-language-translate-the-web.html |url-access=registration |url-status=live |archive-url=https://web.archive.org/web/20150428034914/http://www.newscientist.com/article/mg21328476.200-learn-a-language-translate-the-web.html |archive-date=April 28, 2015 |access-date=August 26, 2017 |magazine=New Scientist}} The founders considered creating Duolingo as a nonprofit organization, but von Ahn judged this model unsustainable. Its early revenue stream, a crowdsourced translation service, was replaced by a Duolingo English Test certification program, advertising, and subscription.{{cite web |last=Lardinois |first=Frederic |date=2015-06-10 |title=Duolingo Raises $45 Million Series D Round Led By Google Capital, Now Valued At $470M |url=https://techcrunch.com/2015/06/10/duolingo-raises-45-million-series-d-round-led-by-google-ventures-now-valued-at-470m/ |url-status=live |archive-url=https://web.archive.org/web/20150804225710/http://techcrunch.com/2015/06/10/duolingo-raises-45-million-series-d-round-led-by-google-ventures-now-valued-at-470m/ |archive-date=4 August 2015 |access-date=2019-12-14 |website=TechCrunch |language=en-US |quote=Instead, the company is now using its Test Center certification program as a revenue source (the tests cost $20) and says that it has other plans to monetize.}}{{cite web |last=Ahn |first=Luis von |date=May 12, 2022 |others=(anonymous) |title=Duol shareholder letter 2022 |url=https://investors.duolingo.com/static-files/d667f9d1-8f7f-418c-b116-e699a30a9826 |url-status=live |archive-url=https://web.archive.org/web/20220512201622/https://investors.duolingo.com/static-files/d667f9d1-8f7f-418c-b116-e699a30a9826 |archive-date=May 12, 2022 |access-date=May 28, 2022 |format=DOC}}

File:Duolingo logo.svg

In October 2011, Duolingo announced that it had raised $3.3 million from a Series A round of funding, led by Union Square Ventures, with participation from author Tim Ferriss and actor Ashton Kutcher's investing firm A-Grade Investments.{{cite news |title=The Daily Start-Up: Kutcher-Backed Language Site Duolingo Finds Its Voice |url=https://blogs.wsj.com/venturecapital/2012/06/19/the-daily-start-up-kutcher-backed-language-site-duolingo-finds-its-voice/ |access-date=2012-07-13 |newspaper=The Wall Street Journal |date=2012-06-19 |archive-date=April 3, 2019 |archive-url=https://web.archive.org/web/20190403191839/https://blogs.wsj.com/venturecapital/2012/06/19/the-daily-start-up-kutcher-backed-language-site-duolingo-finds-its-voice/ |url-status=live }} Duolingo launched a private beta on November 30, 2011, and accumulated a waiting list of more than 100,000 people by December 13.{{cite web |url=https://www.theverge.com/2011/12/16/2639262/duolingo-translate-internet-teach-languages |title=Duolingo will translate the internet while teaching languages |first=Adi |last=Robertson |date=2011-12-16 |website=The Verge |access-date=2016-02-03 |archive-date=January 8, 2012 |archive-url=https://web.archive.org/web/20120108020114/https://www.theverge.com/2011/12/16/2639262/duolingo-translate-internet-teach-languages |url-status=live }}{{Cite news |last=Schwartz |first=Ariel |date=2011-12-13 |title=How The Creator of CAPTCHA Will Translate The Entire Internet |url=https://www.fastcompany.com/1678985/how-the-creator-of-captcha-will-translate-the-entire-internet |archive-url=http://web.archive.org/web/20250131134438/https://www.fastcompany.com/1678985/how-the-creator-of-captcha-will-translate-the-entire-internet |archive-date=2025-01-31 |access-date=2025-02-09 |work=Fast Company |language=en-US}} It launched to the general public on June 19, 2012, at which point the waiting list had grown to around 500,000.{{Cite news |last=Loeb |first=Steven |date=2018-06-22 |title=When Duolingo was young: the early years |url=https://vator.tv/news/2018-06-22-when-duolingo-was-young-the-early-years |url-status=live |archive-url=https://web.archive.org/web/20180625024407/https://vator.tv/news/2018-06-22-when-duolingo-was-young-the-early-years |archive-date=June 25, 2018 |access-date=2019-12-14 |website=VatorNews |at=Duolingo's Third Year}}{{cite web |author=Spice |first=Byron |date= |title=Press Release: Duolingo.com Users Will Translate Web As They Learn a New Language |url=http://www.cmu.edu/news/stories/archives/2012/june/june19_duolingo.html |url-status=live |archive-url=https://web.archive.org/web/20120826233724/http://www.cmu.edu/news/stories/archives/2012/june/june19_duolingo.html |archive-date=August 26, 2012 |access-date=2021-05-14 |website=Carnegie Mellon University |language=en}}

In September 2012, Duolingo announced that it had raised a further $15 million from a Series B funding round led by New Enterprise Associates, with participation from Union Square Ventures.{{cite web |url=https://techcrunch.com/2012/09/17/duolingo-raises-15m-series-b-round-lead-by-nea-will-expand-to-more-languages-and-to-mobile-soon/ |title=Duolingo Raises $15M Series B Round Led By NEA, Will Expand To More Languages And To Mobile Soon |website=TechCrunch |date=2012-09-17 |language=en-US |access-date=2019-12-13 |archive-date=14 December 2019 |archive-url=https://web.archive.org/web/20191214003206/http://social.techcrunch.com/2012/09/17/duolingo-raises-15m-series-b-round-lead-by-nea-will-expand-to-more-languages-and-to-mobile-soon/ |url-status=live }} In November 2012, Duolingo released an iPhone app,{{cite web |url=https://techcrunch.com/2012/11/13/language-learning-service-duolingo-launches-its-first-iphone-app/ |title=Language Learning Service Duolingo Launches Its First iPhone App |first=Frederic |last=Lardinois |date=2012-11-13 |work=TechCrunch |publisher=AOL |access-date=2016-04-18 |archive-date=November 13, 2012 |archive-url=https://web.archive.org/web/20121113205450/https://techcrunch.com/2012/11/13/language-learning-service-duolingo-launches-its-first-iphone-app/ |url-status=live }} followed by an Android app in May 2013, at which time Duolingo had around 3 million users.{{cite web |title=Free Language Learning Service Duolingo Comes To Android |url=https://techcrunch.com/2013/05/29/free-language-learning-service-duolingo-comes-to-android-expects-this-will-double-its-user-base-to-over-6m/ |access-date=2021-05-14 |website=TechCrunch |date=2013-05-29 |language=en-US |archive-date=14 May 2021 |archive-url=https://web.archive.org/web/20210514230149/https://social.techcrunch.com/2013/05/29/free-language-learning-service-duolingo-comes-to-android-expects-this-will-double-its-user-base-to-over-6m/ |url-status=live }} By July 2013, it had grown to 5 million users and was rated the No. 1 free education app in the Google Play Store.{{cite web |url=http://news.cnet.com/8301-1023_3-57593078-93/duolingo-brings-free-language-courses-to-the-ipad/ |title=Duolingo brings free language courses to the iPad |last=Farber |first=Dan |date=2013-07-11 |publisher=C net |access-date=2014-02-21 |archive-date=August 20, 2013 |archive-url=https://web.archive.org/web/20130820163502/http://news.cnet.com/8301-1023_3-57593078-93/duolingo-brings-free-language-courses-to-the-ipad/ |url-status=live }}

In February 2014, Duolingo announced that it had raised $20 million from a Series C funding round led by Kleiner Caufield & Byers, with prior investors also participating.{{cite web |title=Duolingo Raises $20M Series C Led By Kleiner Perkins To Dominate Online Language Learning |url=https://techcrunch.com/2014/02/18/duolingo-raises-20m-series-c-round-led-by-kleiner-perkins-wants-to-dominate-online-language-learning/ |access-date=2021-05-14 |website=TechCrunch |date=2014-02-14 |language=en-US |archive-date=10 March 2015 |archive-url=https://web.archive.org/web/20150310011231/https://social.techcrunch.com/2014/02/18/duolingo-raises-20m-series-c-round-led-by-kleiner-perkins-wants-to-dominate-online-language-learning/ |url-status=live }} At this time, it had 34 employees, and reported about 25 million registered users and 12.5 million active users; it later reported a figure closer to 60 million users.

In June 2015, Duolingo announced that it had raised $45 million from a Series D funding round led by Google Capital, bringing its total funding to $83.3 million. The round valued the company at around $470 million, with 100 million registered users globally.{{cite web |url=https://venturebeat.com/2015/06/10/100m-users-strong-duolingo-raises-45m-led-by-google-at-a-470m-valuation-to-grow-language-learning-platform/ |title=100M users strong, Duolingo raises $45M led by Google at a $470M valuation to grow language-learning platform |date=2015-06-10 |website=VentureBeat |language=en-US |access-date=2019-12-14 |archive-date=June 16, 2015 |archive-url=https://web.archive.org/web/20150616221249/https://venturebeat.com/2015/06/10/100m-users-strong-duolingo-raises-45m-led-by-google-at-a-470m-valuation-to-grow-language-learning-platform/ |url-status=live }} In April 2016, it was reported that Duolingo had more than 18 million monthly users.{{cite web |date=2016 |title=Duolingo Case Study – DynamoDB |url=https://aws.amazon.com/solutions/case-studies/duolingo-case-study-dynamodb/ |url-status=live |archive-url=https://web.archive.org/web/20160628175804/https://aws.amazon.com/solutions/case-studies/duolingo-case-study-dynamodb/ |archive-date=June 28, 2016 |access-date=2019-12-23 |website=Amazon Web Services, Inc. |language=en-US}}{{Citation |title=Duolingo Stores 31 Billion Items on Amazon DynamoDB and Uses AWS to Deliver Language Lessons | date=April 25, 2016 |url=https://www.youtube.com/watch?v=fhnAvn2YxZA |access-date=2019-12-23 |archive-url=https://web.archive.org/web/20201028161357/https://www.youtube.com/watch?v=fhnAvn2YxZA&feature=applinks |archive-date=October 28, 2020 |url-status=live |language=en |via=YouTube}}.

In July 2017, Duolingo announced that it had raised $25 million in a Series E funding round led by Drive Capital, bringing its total funding to $108.3 million. The round valued Duolingo at $700 million, and the company reported passing 200 million registered users, with 25 million active users.{{cite web |url=https://techcrunch.com/2017/07/25/duolingo-raises-25m-at-a-700m-valuation/ |title=Duolingo raises $25M at a $700M valuation |website=TechCrunch |date=2017-07-25 |language=en-US |access-date=2019-12-14 |archive-date=21 April 2019 |archive-url=https://web.archive.org/web/20190421184428/http://social.techcrunch.com/2017/07/25/duolingo-raises-25m-at-a-700m-valuation/ |url-status=live }} It was reported that Duolingo had 95 employees.{{cite press release |url=https://www.prnewswire.com/news-releases/duolingo-now-valued-at-1-5-billion-300968516.html |title=Duolingo Now Valued at $1.5 Billion |last=Duolingo |website=www.prnewswire.com |language=en |access-date=2019-12-14 |archive-date=December 12, 2019 |archive-url=https://web.archive.org/web/20191212102948/https://www.prnewswire.com/news-releases/duolingo-now-valued-at-1-5-billion-300968516.html |url-status=live }} Funds from the Series E round would be directed toward creating initiatives such as a related educational flashcard app, TinyCards, and testbeds for initiatives related to reading and listening comprehension.{{cite web |url=https://www.forbes.com/sites/elaineramirez/2017/09/07/duolingo-korean-language-course-launch/4/#2ecaa1d8739f |title=Duolingo Is Launching A Korean Course To Cash In On Asia's Booming Language Market |last1=Elaine |first1=Ramirez |website=Forbes |access-date=2017-10-11 |archive-date=December 21, 2018 |archive-url=https://web.archive.org/web/20181221041331/https://www.forbes.com/sites/elaineramirez/2017/09/07/duolingo-korean-language-course-launch/4/#2ecaa1d8739f |url-status=live }} On August 1, 2018, Duolingo surpassed 300 million registered users.{{cite web |last=Lardinois |first=Frederic |date=August 2018 |title=Duolingo hires its first chief marketing officer as active user numbers stagnate but revenue grows |url=https://techcrunch.com/2018/08/01/duolingo-hires-its-first-chief-marketing-officer-as-active-user-numbers-stagnate/ |url-status=live |archive-url=https://web.archive.org/web/20190504102838/http://social.techcrunch.com/2018/08/01/duolingo-hires-its-first-chief-marketing-officer-as-active-user-numbers-stagnate/ |archive-date=4 May 2019 |access-date=2019-12-14 |website=TechCrunch |language=en-US}}

In December 2019, it was announced that Duolingo raised $30 million in a Series F funding round from Alphabet's investment company, CapitalG.{{cite web |last=Janardhan |first=Arun |date=2022-05-27 |others=Illustration by Priya Kuriyan |title=Duolingo's Luis von Ahn believes in the power of language |url=https://lifestyle.livemint.com//news/big-story/duolingos-luis-von-ahn-believes-in-the-power-of-language-111653590512842.html |url-status=live |archive-url=https://web.archive.org/web/20220527040040/https://lifestyle.livemint.com//news/big-story/duolingos-luis-von-ahn-believes-in-the-power-of-language-111653590512842.html |archive-date=May 27, 2022 |access-date=2022-05-28 |website=Mintlounge |at=The beginning |language=en}} The round valued Duolingo at $1.5 billion. Duolingo reported 30 million active users at this time. The headcount at the company had increased to around two hundred, and new offices had been opened in Seattle, New York, and Beijing.{{cite web |last=Sawers |first=Paul |date=2019-12-04 |title=Duolingo raises $30 million from Alphabet's CapitalG at $1.5 billion valuation |url=https://venturebeat.com/2019/12/04/duolingo-raises-30-million-from-alphabets-capitalg-at-1-5-billion-valuation/ |url-status=live |archive-url=https://web.archive.org/web/20191204183413/https://venturebeat.com/2019/12/04/duolingo-raises-30-million-from-alphabets-capitalg-at-1-5-billion-valuation/ |archive-date=December 4, 2019 |access-date=2019-12-13 |website=VentureBeat |language=en-US}} Duolingo planned to use the funds to develop new products and further expand its team in sectors like engineering, business development, design, curriculum and content creators, community outreach, and marketing.{{cite web |last=Lindstrom |first=Natasha |date=2019-12-04 |title=Duolingo touts $1.5B valuation; language company to hire 100 more people, mostly in Pittsburgh |url=https://triblive.com/local/pittsburgh-allegheny/duolingo-touts-1-5b-valuation-language-company-to-hire-100-more-people-mostly-in-pittsburgh/ |url-status=live |archive-url=https://web.archive.org/web/20191205133922/https://triblive.com/local/pittsburgh-allegheny/duolingo-touts-1-5b-valuation-language-company-to-hire-100-more-people-mostly-in-pittsburgh/ |archive-date=December 5, 2019 |access-date=2019-12-15 |website=triblive.com}}

File:Duolingo, mem-referenco, 1.jpeg

In October 2013, Duolingo launched a crowdsourced language incubator.{{cite news |last=Munoz |first=Juan Andres |date=2013-10-15 |title=Duolingo 'incubator' aims to crowdsource language teaching |url=https://www.cnn.com/2013/10/15/tech/mobile/duolingo-incubator-language-teaching/index.html |access-date=2022-04-18 |website=CNN |archive-date=April 18, 2022 |archive-url=https://web.archive.org/web/20220418212112/https://www.cnn.com/2013/10/15/tech/mobile/duolingo-incubator-language-teaching/index.html |url-status=live }} In March 2021, it announced that it would be ending its volunteer contributor program. The company said that language courses would instead be maintained and developed by professional linguists aligning with CEFR standards.{{cite web |date=2021-03-10 |title=Ending & honoring our volunteer Contributor program |url=https://blog.duolingo.com/ending-honoring-our-volunteer-contributor-program-2/ |access-date=2022-04-07 |website=Duolingo Blog |language=en |archive-date=March 10, 2021 |archive-url=https://web.archive.org/web/20210310142059/https://blog.duolingo.com/ending-honoring-our-volunteer-contributor-program-2/ |url-status=live }}{{primary inline|date=May 2025}} On June 28, 2021, Duolingo filed for an initial public offering on NASDAQ under the ticker DUOL.{{cite web |last=Sumagaysay |first=Levi |title=Duolingo, the fast-growing language-learning app, files for IPO |url=https://www.marketwatch.com/story/duolingo-the-fast-growing-language-learning-app-files-for-ipo-11624921568 |url-access=subscription |url-status=live |archive-url=https://web.archive.org/web/20210628232435/https://www.marketwatch.com/story/duolingo-the-fast-growing-language-learning-app-files-for-ipo-11624921568 |archive-date=June 28, 2021 |access-date=2021-07-05 |website=MarketWatch |language=EN-US |format=IPO Report}} From August 2021 to June 2022, the Duolingo language learning app was removed from some app stores in China.{{Cite web |title=Duolingo back in China app stores after 1 year |url=https://techcrunch.com/2022/06/09/duolingo-back-in-china/ |archive-url=https://web.archive.org/web/20220610220221/https://techcrunch.com/2022/06/09/duolingo-back-in-china/ |url-status=dead |archive-date=June 10, 2022 |access-date=2022-07-26 |website=TechCrunch |date=2022-06-10 |language=en-US }}

In August 2022, Duolingo overhauled its interface, changing its course structure from a tree-like design, where users could choose from a range of lessons after completing previous ones, to a linear progression. This update has been criticized by users across social media outlets, such as Reddit and Twitter.{{cite news |last1=Gifford |first1=Bill |title=Can Duolingo Actually Teach You Spanish? |url=https://www.bloomberg.com/news/features/2022-12-02/duolingo-plus-gave-fans-of-free-app-a-cost-worth-paying |access-date=2022-12-02 |work=Bloomberg Businessweek |date=2022-12-02 |language=en |archive-date=December 2, 2022 |archive-url=https://web.archive.org/web/20221202175759/https://www.bloomberg.com/news/features/2022-12-02/duolingo-plus-gave-fans-of-free-app-a-cost-worth-paying |url-status=live }} CEO Luis von Ahn stated that there were no plans to reverse the changes.{{cite news |last=Goggin |first=Ben |date=2022-08-26 |title=Duolingo's redesign has some fans up in arms. Its CEO says it's not turning back. |url=https://www.nbcnews.com/tech/tech-news/duolingos-update-redesign-luis-von-ahn-interview-rcna44655 |url-status=live |archive-url=https://web.archive.org/web/20220826235521/https://www.nbcnews.com/tech/tech-news/duolingos-update-redesign-luis-von-ahn-interview-rcna44655 |archive-date=August 26, 2022 |access-date=2022-08-26 |work=NBC News}} In October 2022, Duolingo acquired Detroit-based animation studio Gunner; it is the studio that produces art assets and animation for Duolingo and Duolingo ABC and its marketing campaigns.{{cn|date=May 2025}}

In March 2023, Duolingo officially announced the planned Duolingo Max, a subscription tier above Super Duolingo, in their blog.{{Cite web |date=2023-03-14 |title=Introducing Duolingo Max, a learning experience powered by GPT-4 |url=https://blog.duolingo.com/duolingo-max/ |access-date=2024-04-24 |website=Duolingo Blog |language=en}} In October 2023, Duolingo released math and music courses in English and Spanish for iOS users.{{cite web |last1=Lang |first1=Jamie |date=5 October 2022 |title=Duolingo Acquires Detroit-Based Design And Animation Studio Gunner |url=https://www.cartoonbrew.com/studios/duolingo-acquires-gunner-animation-studio-221889.html |archive-url=https://web.archive.org/web/20230323013228/https://www.cartoonbrew.com/studios/duolingo-acquires-gunner-animation-studio-221889.html |archive-date=23 March 2023 |access-date=16 July 2023 |website=Cartoon Brew}}{{Cite web |date=2023-10-11 |title=One app to school them all: the expanded Duolingo 🎶 ➗ 🇲🇽 |url=https://blog.duolingo.com/new-subjects/ |url-status=live |archive-url=https://web.archive.org/web/20231011165653/https://blog.duolingo.com/new-subjects/ |archive-date=October 11, 2023 |access-date=2023-10-11 |website=Duolingo Blog |language=en}}

In January 2024, Duolingo fired some contractors and announced plans to replace them with AI.{{Cite web |last=Korn |first=Jennifer |date=January 9, 2024 |editor-last=Thorbecke |editor-first=Catherine |others=Contributed by Catherine Thorbecke |title=Duolingo lays off staff as language learning app shifts toward AI |url=https://edition.cnn.com/2024/01/09/tech/duolingo-layoffs-due-to-ai/index.html |url-status=live |archive-url=https://web.archive.org/web/20240111082828/https://edition.cnn.com/2024/01/09/tech/duolingo-layoffs-due-to-ai/index.html |archive-date=January 11, 2024 |access-date=January 11, 2024 |website=CNN}}{{Cite web |last=Nolan |first=Beatrice |date=January 10, 2024 |title=Duolingo lays off workers as it leans on AI tools to carry out more tasks |url=https://www.businessinsider.com/duolingo-lays-off-workers-ai-tools-2024-1 |url-access=subscription |url-status=live |archive-url=https://web.archive.org/web/20240111020531/https://www.businessinsider.com/duolingo-lays-off-workers-ai-tools-2024-1 |archive-date=January 11, 2024 |access-date=January 11, 2024 |website=Business Insider}} The company acquired Detroit-based design studio Hobbes in March.{{Cite web |last=Perez |first=Sarah |date=2024-07-09 |title=Duolingo acquires Detroit-based design studio Hobbes |url=https://techcrunch.com/2024/07/09/duolingo-acquires-detroit-based-design-studio-hobbes/ |access-date=2024-07-14 |website=TechCrunch |language=en-US}}

CEFR based language courses for learners of English, Spanish, French, Italian, Chinese (Mandarin), Japanese, Korean, Portuguese, and German are available for all users.{{Cite web |title=Unofficial Duolingo Course Data |url=https://duolingodata.com/ |access-date=2025-01-23 |website=duolingodata.com}} Additional courses are also available for speakers of English (Arabic, Czech, Danish, Dutch, Esperanto, Finnish, Greek, Haitian Creole, Hawaiian, Hebrew, High Valyrian, Hindi, Hungarian, Indonesian, Irish, Klingon, Latin, Navajo, Norwegian, Polish, Romanian, Russian, Scottish Gaelic, Swahili, Swedish, Turkish, Ukrainian, Vietnamese, Welsh, Yiddish, Zulu), Chinese (Chinese (Cantonese)), Arabic (Swedish), and Spanish (Catalan, Russian, Swedish).{{update inline|date=May 2025}}

As of 2014, most of Duolingo's language learning features are free with advertising. Users can remove advertising by paying a subscription fee or promoting referral links.{{cite web |last=Olson |first=Parmy |date=January 22, 2014 |title=Crowdsourcing Capitalists: How Duolingo's Founders Offered Free Education To Millions |url=https://www.forbes.com/sites/parmyolson/2014/01/22/crowdsourcing-capitalists-how-duolingos-founders-offered-free-education-to-millions/ |url-status=live |archive-url=https://web.archive.org/web/20140127012240/https://www.forbes.com/sites/parmyolson/2014/01/22/crowdsourcing-capitalists-how-duolingos-founders-offered-free-education-to-millions/ |archive-date=January 27, 2014 |access-date=2015-12-22 |website=Forbes}} The paid user program, Super Duolingo (formerly known as Duolingo Plus), offers unlimited retries and access to some additional types of lessons. It is otherwise identical to Duolingo for Schools.{{cite web |title=What is Super Duolingo? |url=https://support.duolingo.com/hc/en-us/articles/115004068043-What-is-Super-Duolingo- |url-status=live |archive-url=https://web.archive.org/web/20230929161814/https://support.duolingo.com/hc/en-us/articles/115004068043-What-is-Super-Duolingo- |archive-date=September 29, 2023 |access-date=16 July 2023 |website=Duolingo Help Center}}{{cite web |title=Super Duolingo |url=https://duolingo.com/super |website=Super Duolingo homepage |access-date=22 November 2024}}{{primary inline|date=May 2025}}

Duolingo Max is a subscription above Super Duolingo that adds additional functions using generative AI: Roleplay, an AI conversation partner; Explain My Answer, which breaks down the rules with a modified GPT-4 when the user makes a mistake; and Video Call, where users can have video chat with one of the characters, which currently only includes Lily. Intended to provide immersion through conversation.{{Cite web |last1=Bodge |first1=Edwin |last2=Peterson |first2=Bill |date=March 14, 2023 |title=OpenAI customer story: Duolingo |url=https://openai.com/customer-stories/duolingo |access-date=April 24, 2024 |website=OpenAI |language=en-US}}{{primary inline|date=May 2025}}

Duolingo for Schools is designed to help teachers use Duolingo in their classrooms. It allows teachers to create classrooms, assign lessons, track student progress, and personalize learning.{{Cite web |title=Duolingo for Schools |url=https://schools.duolingo.com/ |access-date=2024-09-08 |website=schools.duolingo.com}}{{primary inline|date=May 2025}}

{{main|Duolingo English Test}}

The Duolingo English Test (DET) is an online English proficiency test that measures proficiency in reading, writing, speaking, and listening in English. It is a computer-based test scored on a scale of 10–160, with scores above 120 considered English proficiency. The test's questions algorithmically adjust to the test-takers' ability level. The test's certificate is reportedly accepted by over 5,500 programs internationally,{{Cite web |last=Lal |first=Preeti Verma |date=March 10, 2024 |title=Study Abroad: All About Duolingo English Test accepted by over 5,000 programs worldwide |url=https://www.hindustantimes.com/education/study-abroad-all-about-duolingo-english-test-accepted-by-over-5-000-programs-worldwide-101710053253295.html |url-status=live |archive-url=https://web.archive.org/web/20240606033437/https://www.hindustantimes.com/education/study-abroad-all-about-duolingo-english-test-accepted-by-over-5-000-programs-worldwide-101710053253295.html |archive-date=June 6, 2024 |access-date=June 7, 2024 |website=Hindustan Times}} albeit with exceptions.{{Cite web |last=Durrani |first=Anayat |date=December 8, 2023 |title=Duolingo English Test and U.S. College Admissions |url=https://www.usnews.com/education/best-global-universities/articles/duolingo-english-test-and-u-s-college-admissions |url-status=live |archive-url=https://web.archive.org/web/20240526041815/https://www.usnews.com/education/best-global-universities/articles/duolingo-english-test-and-u-s-college-admissions |archive-date=May 26, 2024 |access-date=June 7, 2024 |website=U.S. News & World Report}}

Duolingo Math is an app course for learning elementary mathematics. It was announced on YouTube on August 27, 2022.{{Cite AV media |url=https://www.youtube.com/watch?v=ejr7g6riodk&ab_channel=Duolingo |title=Duolingo's Path to Math! • Sammi Siegel • Duocon 2022 |date=August 27, 2022 |last=Siegel |first=Sammi |type=Video |language=en |publisher=Duolingo |series=Duocon 2022 |via=YouTube}}

On October 11, 2023, the company released Duolingo Music, a new platform within the existing app that provides basic music learning through piano and sheet music lessons.{{Cite web |last=Perez |first=Sarah |date=2023-09-06 |title=Duolingo confirms its app will soon include both math and music lessons |url=https://techcrunch.com/2023/09/06/duolingo-confirms-its-app-will-soon-include-both-math-and-music-lessons/ |url-status=live |archive-url=https://web.archive.org/web/20231007163720/https://techcrunch.com/2023/09/06/duolingo-confirms-its-app-will-soon-include-both-math-and-music-lessons/ |archive-date=October 7, 2023 |access-date=2023-10-06 |website=TechCrunch |language=en-US}}{{Cite web |author1=Cesar Cadenas |date=2023-10-11 |title=Duolingo's new Music platform will teach you the basics of playing tunes |url=https://www.techradar.com/computing/software/duolingos-new-music-platform-will-teach-you-the-basics-of-playing-tunes |url-status=live |archive-url=https://web.archive.org/web/20231011110233/https://www.techradar.com/computing/software/duolingos-new-music-platform-will-teach-you-the-basics-of-playing-tunes |archive-date=October 11, 2023 |access-date=2023-10-11 |website=TechRadar |language=en}}

Duolingo introduced chess lessons in beta in April 2025, with an initial rollout planned for iOS in English by May. The lessons are structured around the Elo rating system, gradually increasing in difficulty to match the user's skill level. Learners can play mini-matches or full games against Duolingo’s virtual chess coach, Oscar, whose difficulty also scales with progress. At launch, users are not able to play against each other.{{Cite web |last=STAFF |first=GEEK |date=2025-04-15 |title=Duolingo adds chess lessons to iPhone app: here's what to expect |url=https://www.absolutegeeks.com/article/tech-news/duolingo-adds-chess-lessons-to-iphone-app-heres-what-to-expect/?feed_id=13792&_unique_id=67fe0aed22ce2 |access-date=2025-04-16 |website=Absolute Geeks |language=en-US}}{{Cite web |last=Deto |first=Ryan |date=2025-04-22 |title=Duolingo expands app with chess launch |url=https://www.axios.com/local/pittsburgh/2025/04/22/duolingo-chess-learning-app-launch |access-date=2025-04-22 |website=Axios |language=en}}

Duolingo ABC is a free app designed for young children to learn letters, their sounds, phonics, and other early reading concepts. Released in 2020, it does not contain ads or in-app purchases. As of April 2024, iOS and Android versions are available, but only in English.{{cite web |date=2020-08-26 |title=Duolingo ABC: Unlocking the magic of reading |url=https://blog.duolingo.com/duolingo-abc-unlocking-the-magic-of-reading/ |access-date=2022-05-31 |website=Duolingo Blog |language=en |archive-date=May 18, 2022 |archive-url=https://web.archive.org/web/20220518162935/https://blog.duolingo.com/duolingo-abc-unlocking-the-magic-of-reading/ |url-status=live }}

On Duolingo, learners learn by doing, engaging with the course material.{{Cite AV media |url=https://www.youtube.com/watch?v=OVTSGL4BdDU |title=Introducing The Duolingo Method - How does Duolingo teach new subjects? |date=2023-10-11 |last=Duolingo |access-date=2024-08-02 |via=YouTube}} Lessons are designed to be brief, allowing users to learn in manageable chunks.{{cite web |last1=Pajak |first1=Bozena |last2=Tsai |first2=Karin |date=2019-12-11 |title=How we've improved the Duolingo learning experience this year (and a sneak peek toward 2020!) |url=https://blog.duolingo.com/how-weve-improved-the-duolingo-learning-experience-this-year-and-a-sneak-peek-toward-2020/ |url-status=live |archive-url=https://web.archive.org/web/20210730021026/https://blog.duolingo.com/how-weve-improved-the-duolingo-learning-experience-this-year-and-a-sneak-peek-toward-2020/ |archive-date=July 30, 2021 |access-date=2021-08-26 |website=Duolingo Blog |language=en}}{{cite web |title=Duolingo |url=http://www.tesl-ej.org/pdf/ej73/m1.pdf |url-status=live |archive-url=https://web.archive.org/web/20220122002600/http://www.tesl-ej.org/pdf/ej73/m1.pdf |archive-date=January 22, 2022 |access-date=December 31, 2021 |website=TESL-EJ}} Duolingo uses a gamified approach to learning, with lessons that incorporate translating, interactive exercises, quizzes, and stories.{{cite web |last=Brockbank |first=Dayna |date=2020-10-05 |title=Everything You Need to Know About Duolingo Stories • Happily Ever Travels |url=https://happilyevertravels.com/duolingo-stories/ |url-status=live |archive-url=https://web.archive.org/web/20211007091457/https://happilyevertravels.com/duolingo-stories/ |archive-date=October 7, 2021 |access-date=2021-08-26 |website=Happily Ever Travels |language=en-US}} It also uses an algorithm that adapts to each learner and can provide personalized feedback and recommendations.

Duolingo provides a competitive space,{{Cite book |last=Fians |first=Guilherme |url=https://link.springer.com/book/10.1007/978-3-030-84230-7 |title=Esperanto Revolutionaries and Geeks: Language Politics, Digital Media and the Making of an International Community |publisher=Palgrave Macmillan |year=2021 |isbn=978-3-030-84229-1 |location=London and New York |language=en |doi=10.1007/978-3-030-84230-7 |access-date=December 2, 2022 |archive-url=https://web.archive.org/web/20221031094243/https://link.springer.com/book/10.1007/978-3-030-84230-7 |archive-date=October 31, 2022 |url-status=live |s2cid=245721938}} such as in leagues, where people can compete with randomly selected worldwide player groupings of up to 30 users. Leagues: Bronze, Silver, Gold, Sapphire, Ruby, Emerald, Amethyst, Pearl, Obsidian, Diamond. Rankings in leagues are determined by the number of experience points earned in a week. Badges in Duolingo represent achievements earned from completing specific objectives.{{Cite book |last1=Huynh |first1=Duy |title=Games and Learning Alliance |last2=Zuo |first2=Long |last3=Iida |first3=Hiroyuki |publisher=Springer, Cham |year=2016 |isbn=978-3319501819 |series=Lecture Notes in Computer Science |volume=10056 |pages=268–277 |language=en |chapter=Analyzing Gamification of "Duolingo" with Focus on its Course Structure |doi=10.1007/978-3-319-50182-6_24}} Users can also create their own avatars.{{Cite AV media |url=https://www.youtube.com/watch?v=i0YT9VQh4FY |title=Duolingo Clash |date=2024-09-07 |last=Duolingo Path |access-date=2024-09-08 |via=YouTube}}{{Cite web |date=2023-07-19 |title=Become a Duolingo character with our new Avatars! |url=https://blog.duolingo.com/avatar-creator/ |access-date=2024-09-08 |website=Duolingo Blog |language=en}}

Any lesson completed in Duolingo will count towards the user's daily streak.{{Cite web |date=2023-10-11 |title=Duolingo is bringing language, math, and music under one roof! |url=https://blog.duolingo.com/new-subjects/ |access-date=2024-04-25 |website=Duolingo Blog |language=en}} The daily streak's visual symbol in the app is fire. Duolingo's "Friend Streak" lets users maintain streaks with up to five friends.{{Cite web |date=2024-08-05 |title=Friend Streak: a new way to stay motivated together |url=https://blog.duolingo.com/friend-streak/ |access-date=2024-09-08 |website=Duolingo Blog |language=en}} Streaks encourage consistent daily practice and help build a habit of regular learning.

The app has a personalized bandit algorithm system (later the A/B tested variant recovering difference softmax algorithm) that determines the daily notification that will be sent out to the user.{{Cite book |last1=Yancey |first1=Kevin P. |title=Proceedings of the 26th ACM SIGKDD International Conference on Knowledge Discovery & Data Mining |last2=Settles |first2=Burr |date=August 20, 2020 |publisher=Association for Computing Machinery |isbn=978-1-4503-7998-4 |location=California, United States |pages=3008–3016 |chapter=A Sleeping, Recovering Bandit Algorithm for Optimizing Recurring Notifications |doi=10.1145/3394486.3403351 |chapter-url=https://research.duolingo.com/papers/yancey.kdd20.pdf?ref=blog.duolingo.com |doi-access=free}}

The Duolingo Score is an estimate of users’ proficiency in the language they're learning in CEFR-aligned courses. Duolingo Score provides a granular assessment of what a student has learned and they can do with the language.{{Cite web |last=Yang |first=Kevin |date=2024-10-23 |title=The Duolingo Score Tracks Your Learning Progress |url=https://blog.duolingo.com/duolingo-score/ |access-date=2025-01-28 |website=Duolingo Blog |language=en}} DET is using a similar scoring system. The most developed CEFR-aligned courses (French, English and Spanish) cover Duolingo Score from 0 to 130.

Duolingo operates on a freemium business model, offering free access to its learning platforms with ads. Revenue is primarily generated through subscriptions, which remove ads, and provide other perks like unlimited hearts and generative AI. The app also generates income from in-app purchases of virtual currency (Gems) and power-ups that enhance the learning experience. Another key revenue stream is the Duolingo English Test (DET), a low-cost English proficiency test.{{cite web |title=Duolingo shareholder letter 2022 |url=https://investors.duolingo.com/static-files/d667f9d1-8f7f-418c-b116-e699a30a9826 |access-date=May 28, 2022 |archive-date=May 12, 2022 |archive-url=https://web.archive.org/web/20220512201622/https://investors.duolingo.com/static-files/d667f9d1-8f7f-418c-b116-e699a30a9826 |url-status=live }}

In April 2020, it passed one million paid subscribers;{{cite web|last=Doughty |first=Nate |date=2020-04-08 |title=Duolingo passes one million paid users, expands with new hires |url=https://www.bizjournals.com/pittsburgh/news/2020/04/08/duolingo-passes-one-million-paid-users-expands.html |url-status=live |archive-url=https://web.archive.org/web/20210122184639/https://www.bizjournals.com/pittsburgh/news/2020/04/08/duolingo-passes-one-million-paid-users-expands.html |archive-date=2021-01-22 |access-date=2020-12-12 |website=Pittsburgh Business Times}} it reached 2.9 million in March 2022,{{cite web |title=Duolingo Announces Record Bookings in First Quarter 2022 and Raises Full Year Guidance |url=https://www.nasdaq.com/press-release/duolingo-announces-record-bookings-in-first-quarter-2022-and-raises-full-year |access-date=May 25, 2022 |archive-date=May 25, 2022 |archive-url=https://web.archive.org/web/20220525040104/https://www.nasdaq.com/press-release/duolingo-announces-record-bookings-in-first-quarter-2022-and-raises-full-year |url-status=live }} and 4.8 million at the end of March 2023.{{Cite web |url=https://investors.duolingo.com/static-files/3c5dd359-4936-452a-9d9f-9a8c853c06c0 |title=Duolingo Reports 62% DAU Growth, 42% Revenue Growth, and Increased Profitability in First Quarter 2023; Raises Full Year Guidance |access-date=May 31, 2023 |archive-date=May 31, 2023 |archive-url=https://web.archive.org/web/20230531171944/https://investors.duolingo.com/static-files/3c5dd359-4936-452a-9d9f-9a8c853c06c0 |url-status=live }} As of June 2024 Duolingo has 8 million paying subscribers.

Duolingo had revenue of $531 million in 2023, compared to $250.77 million in 2021,{{cite web |last=Shijia |first=Ouyang |date=13 December 2019 |title=Language-learning app Duolingo bullish on Chinese market |url=https://www.chinadaily.com.cn/a/201912/13/WS5df2ebe7a310cf3e3557de46.html |url-status=live |archive-url=https://web.archive.org/web/20191214041809/https://www.chinadaily.com.cn/a/201912/13/WS5df2ebe7a310cf3e3557de46.html |archive-date=December 14, 2019 |access-date=2019-12-14 |website=China Daily}} $36 million in 2018,{{cite web |last=Adams |first=Susan |title=Game of Tongues: How Duolingo Built A $700 Million Business With Its Addictive Language-Learning App |url=https://www.forbes.com/sites/susanadams/2019/07/16/game-of-tongues-how-duolingo-built-a-700-million-business-with-its-addictive-language-learning-app/ |url-status=live |archive-url=https://web.archive.org/web/20190723122302/https://www.forbes.com/sites/susanadams/2019/07/16/game-of-tongues-how-duolingo-built-a-700-million-business-with-its-addictive-language-learning-app/ |archive-date=July 23, 2019 |access-date=2019-12-14 |website=Forbes |language=en}} $13 million in 2017, and $1 million in 2016. In May 2022, it was reported that 6.8% of its monthly active users paid for the ad-free version of the app.{{Cite web |date=May 19, 2022 |title=Duolingo CEO talks earnings, paid subscribers, and the stock's performance |url=https://finance.yahoo.com/video/duolingo-ceo-talks-earnings-paid-144115465.html |url-status=live |archive-url=https://web.archive.org/web/20220519145317/https://finance.yahoo.com/video/duolingo-ceo-talks-earnings-paid-144115465.html |archive-date=May 19, 2022 |access-date=8 August 2024 |website=Yahoo! Finance |type=an article with a transcription from a video report}}

A 2017 study found no significant difference between elementary students learning Spanish through the "gamification" of the Duolingo app and those learning in classroom environments, with both groups demonstrating a similar increase in achievements and self-efficacy.{{cite journal |last1=Rachels |first1=Jason R. |last2=Rockinson-Szapkiw |first2=Amanda J. |year=2018 |title=The effects of a mobile gamification app on elementary students' Spanish achievement and self-efficacy |journal=Computer Assisted Language Learning |publisher=Routledge |volume=31 |issue=1–2 |pages=72–89 |doi=10.1080/09588221.2017.1382536 |s2cid=67064098}}

Duolingo's occasional use of 'erratic' phrases—such as "The bride is a woman and the groom is a hedgehog" or "The man eats ice cream with mustard"{{Cite news |last=Hu |first=Jane C. |date=2021-11-29 |title=Why Are Duolingo's Sentences So Weird? |url=https://slate.com/technology/2021/11/duolingo-weird-sentences-linguistics.html |access-date=2024-07-26 |work=Slate |language=en-US |issn=1091-2339}}—is reportedly derived from research published in 2018 by psychologists at Ghent University in Belgium,{{Cite journal |last1=Loof |first1=Esther De |last2=Ergo |first2=Kate |last3=Naert |first3=Lien |last4=Janssens |first4=Clio |last5=Talsma |first5=Durk |last6=Opstal |first6=Filip Van |last7=Verguts |first7=Tom |date=2018-01-02 |title=Signed reward prediction errors drive declarative learning |journal=PLOS ONE |language=en |volume=13 |issue=1 |pages=e0189212 |doi=10.1371/journal.pone.0189212 |doi-access=free |issn=1932-6203 |pmc=5749691 |pmid=29293493|bibcode=2018PLoSO..1389212D }} which concluded that such "semantically unpredictable sentences" were more effective for language learning than conventional and predictable phrases, based on the concept of "reward prediction errors", in which unexpected or surprising outcomes are more rewarding and thus encourage further learning.{{Cite journal |last1=Benoît |first1=Christian |last2=Grice |first2=Martine |last3=Hazan |first3=Valérie |date=1996 |title=The SUS test: A method for the assessment of text-to-speech synthesis intelligibility using Semantically Unpredictable Sentences |url=https://www.sciencedirect.com/science/article/abs/pii/016763939600026X?via%253Dihub |journal=Speech Communication |volume=18 |issue=4 |pages=381–392 |doi=10.1016/0167-6393(96)00026-X}}

A 2022 study on adults using Duolingo as their only language learning tool, published in the journal Foreign Language Annals, found that participants who completed a course had similar reading and listening proficiency to university students after four semesters of study, concluding that Duolingo could be an effective tool for language learning.{{Cite journal |last1=Jiang |first1=Xiangying |last2=Rollinson |first2=Joseph |last3=Plonsky |first3=Luke |last4=Gustafson |first4=Erin |last5=Pajak |first5=Bozena |date=2022-01-11 |title=Evaluating the reading and listening outcomes of beginning-level Duolingo courses |journal=Foreign Language Annals |language=en |volume=54 |issue=4 |pages=974–1002 |doi=10.1111/flan.12600 |issn=0015-718X |s2cid=245892888 |doi-access=free}} Another 2022 study of Malaysian students learning French, published by the National University of Malaysia Press, found that the app facilitated the acquisition of vocabulary and concluded that it was "well suited" for beginners in this regard.{{cite journal |last1=Saad |first1=Suziana Mat |last2=Rahim |first2=Nur Ameera Abd |year=2022 |title=Vocabulary Acquisition Using Duolingo in French Language Learning: A Malaysian Context |url=https://ejournal.ukm.my/ebangi/article/view/54226/12880 |journal=E-Bangi: Journal of Social Sciences & Humanities |volume=19 |issue=2 |pages=256–281 |eissn=1823-884X}}

According to Duolingo's own 2021 study, five sections of the app are roughly equivalent to five semesters of university instruction, and Duolingo is an "effective tool [...] at an intermediate level".{{Cite web |title=Duolingo Really Works - Learn more about how Duolingo works for learners |url=https://www.duolingo.com/efficacy |url-status=live |archive-url=https://web.archive.org/web/20240530223517/https://www.duolingo.com/efficacy |archive-date=May 30, 2024 |access-date=2024-06-06 |website=Duolingo}}{{Cite journal |last1=Jiang |first1=Xiangying |last2=Chen |first2=Haoyu |last3=Portnof |first3=Lucy |last4=Gustafson |first4=Erin |last5=Rollinson |first5=Joseph |last6=Plonsky |first6=Luke |last7=Pajak |first7=Bozena |date=November 11, 2021 |title=Finishing half of B1 on Duolingo comparable to five university semesters in reading and listening |url=https://duolingo-papers.s3.amazonaws.com/reports/Duolingo_whitepaper_language_read_listen_2021.pdf |url-status=live |journal=Duolingo |id=DRR-21-03 |archive-url=https://web.archive.org/web/20240602232722/https://duolingo-papers.s3.amazonaws.com/reports/Duolingo_whitepaper_language_read_listen_2021.pdf |archive-date=June 2, 2024}} A 2023 study funded by Duolingo concluded that Duolingo English learners did not significantly learn much grammar.{{Cite journal |last1=Rodríguez-Fuentes |first1=Rodrigo A. |last2=Swatek |first2=Aleksandra |date=December 14, 2023 |editor-last=Ariel |editor-first=Robert |editor2-last=Jiang |editor2-first=Xiangying |title=A Comparison Between Classroom and MALL Instruction with Duolingo: Learning English at the A2 CEFR Level |url=https://duolingo-papers.s3.amazonaws.com/reports/RodriguezFuentes_etal_whitepaper_language_proficiency_Columbia_2023.pdf |journal=Amazon Web Services}} Duolingo English learners in Colombia and Spain were found to gain significantly more proficiency than students in a classroom, except for listening.{{Cite journal |last=González-Fernández |first=Beatriz |date=November 30, 2023 |title=The effectiveness of Duolingo vs. classroom instruction on Spanish speakers' L2 English proficiency and lexical development |url=https://duolingo-papers.s3.amazonaws.com/reports/GonzalezFernandez_whitepaper_language_proficiency_Spain_2023.pdf |url-status=live |journal=Amazon Web Services |archive-url=https://web.archive.org/web/20240602133716/https://duolingo-papers.s3.amazonaws.com/reports/GonzalezFernandez_whitepaper_language_proficiency_Spain_2023.pdf |archive-date=June 2, 2024}}

Some language professionals have criticized the app for its limitations and gamified design.{{cite web |last1=Heaney |first1=Katie |date=January 25, 2019 |title=Is It Just Me, or Does Duolingo Not Work? |url=https://www.thecut.com/2019/01/does-duolingo-even-work.html |url-access=limited |url-status=live |archive-url=https://web.archive.org/web/20190709193541/https://www.thecut.com/2019/01/does-duolingo-even-work.html |archive-date=July 9, 2019 |access-date=24 November 2023 |website=The Cut}} Players have also reported that "gamification" has led to cheating, hacking, and incentivized game strategies that conflict with actual learning.{{cite web |last1=Guthrie |first1=Robert |date=5 June 2023 |title=Duolingo Is An App For Language-Learning, So Why Is It Plagued With Cheaters? |url=https://kotaku.com/duolingo-app-cheats-hacks-leagues-xp-why-duohacker-1850506482 |url-status=live |archive-url=https://web.archive.org/web/20230606135117/https://kotaku.com/duolingo-app-cheats-hacks-leagues-xp-why-duohacker-1850506482 |archive-date=June 6, 2023 |access-date=6 June 2023 |website=Kotaku |language=en}}

In March 2022, Duolingo forums were discontinued,{{Cite web |title=Forum Announcement + FAQ |url=https://support.duolingo.com/hc/en-us/articles/4424678300301-Forum-Announcement-FAQ |url-status=dead |archive-url=https://web.archive.org/web/20240304092005/https://support.duolingo.com/hc/en-us/articles/4424678300301-Forum-Announcement-FAQ |archive-date=March 4, 2024 |access-date=June 6, 2024 |website=Duolingo}} and sentence discussions became read-only.{{Cite web |title=How do I report a problem with a sentence or translation? |url=https://support.duolingo.com/hc/en-us/articles/204752124-How-do-I-report-a-problem-with-a-sentence-or-translation |url-status=live |archive-url=https://web.archive.org/web/20230923031515/https://support.duolingo.com/hc/en-us/articles/204752124-How-do-I-report-a-problem-with-a-sentence-or-translation- |archive-date=September 23, 2023 |access-date=August 12, 2024 |website=Duolingo}} The change has been criticized on some social media sites.

In January 2023, Duolingo's data on over 2.6 million users' usernames, names, and phone numbers was sold in a hacker forum. Duolingo later stated that they would investigate the "dark web post".{{Cite web |last=Greig |first=Jonathan |date=January 24, 2023 |title=DuoLingo investigating dark web post offering data from 2.6 million accounts |url=https://therecord.media/duolingo-investigating-dark-web-post-offering-data-from-2-6-million-accounts |url-status=live |archive-url=https://web.archive.org/web/20231012025712/https://therecord.media/duolingo-investigating-dark-web-post-offering-data-from-2-6-million-accounts |archive-date=October 12, 2023 |access-date=2024-06-06 |website=The Record}} They concluded that the data was obtained by scraping publicly available information based on an exposed application programming interface (API).{{Cite web |last=Mascellino |first=Alessandro |date=2023-08-24 |title=Data of 2.6M Duolingo Users Leaked on Hacking Forum |url=https://www.infosecurity-magazine.com/news/data-26m-duolingo-users-leaked/ |url-status=live |archive-url=https://web.archive.org/web/20240221023819/https://www.infosecurity-magazine.com/news/data-26m-duolingo-users-leaked/ |archive-date=February 21, 2024 |access-date=2024-06-06 |website=Infosecurity Magazine |language=en-gb}}{{Cite web |last=Naprys |first=Ernestas |date=November 15, 2023 |title=Hackers exposed 2.6 million Duolingo users, more available for scraping |url=https://cybernews.com/security/hackers-exposed-duolingo-users-more-available-scraping/ |url-status=live |archive-url=https://web.archive.org/web/20240303083615/https://cybernews.com/security/hackers-exposed-duolingo-users-more-available-scraping/ |archive-date=March 3, 2024 |access-date=June 6, 2024 |website=Cybernews}} Duolingo's spokesperson states that the API is intentionally publicly visible.

Since the end of October 2023, Duolingo has stopped updating its Welsh course to "focus on languages in higher demand". Some users criticized this decision because it came at the expense of learners of a language with limited resources on the market and the potential halting of the Welsh Government{{'s}} "Cymraeg 2050" strategy to promote Welsh language learning.{{Cite news |last1=McCarthy |first1=James |last2=Evans |first2=Owain |date=October 24, 2023 |others=Additional reporting by Dan Moffat |title=Welsh course to be 'paused' on language app Duolingo |url=https://www.bbc.com/news/uk-wales-67197462 |url-status=live |archive-url=https://web.archive.org/web/20240210181414/https://www.bbc.com/news/uk-wales-67197462 |archive-date=10 February 2024 |access-date=27 March 2024 |agency=BBC}}{{Cite news |last=Aitken |first=Catriona |date=2023-10-30 |title=Duolingo: Language app boss to help Welsh language goal |url=https://www.bbc.com/news/uk-wales-67260479 |url-status=live |archive-url=https://web.archive.org/web/20240404153208/https://www.bbc.com/news/uk-wales-67260479 |archive-date=April 4, 2024 |access-date=2024-06-07 |work=BBC News |language=en-GB}}

Duolingo courses vary greatly in quality. While most popular language courses like Spanish or French are well developed, other courses for less studied languages like Ukrainian cover very little grammar and vocabulary.{{Cite book |last=Estigarribia |first=Bruno |url=https://directory.doabooks.org/handle/20.500.12854/74732 |title=A Grammar of Paraguayan Guarani |publisher=UCL Press |year=2020 |isbn=978-1-78735-287-2 |location=London |pages=23 |doi=10.14324/111.9781787352872 |jstor=j.ctv13xpscn}}{{Cite web |title=Unofficial Duolingo Course Data |url=https://duolingodata.com/ |access-date=2025-02-04 |website=duolingodata.com}}

In 2013, Apple chose Duolingo as its iPhone App of the Year, a first for an educational application.{{cite web |last=Hockenson |first=Lauren |date=2013-12-17 |title=Duolingo snags iPhone App of the Year |url=http://gigaom.com/2013/12/17/duolingo-snags-iphone-app-of-the-year/ |url-status=dead |archive-url=https://web.archive.org/web/20201112020859/https://gigaom.com/2013/12/17/duolingo-snags-iphone-app-of-the-year/ |archive-date=12 November 2020 |access-date=2014-02-21 |publisher=Gigaom}} That year, Duolingo ranked No.{{Nbsp}}7 on Fast Company{{'s}} "The World's Most Innovative Companies: Education Honorees" list "for crowdsourcing web translation by turning it into a free language-learning program".{{cite web |title=The World's Most Innovative Companies 2013: Education Honorees |url=https://www.fastcompany.com/most-innovative-companies/2013/sectors/education |access-date=2019-12-14 |website=Fast Company |language=en-US |archive-date=July 23, 2019 |archive-url=https://web.archive.org/web/20190723152111/https://www.fastcompany.com/most-innovative-companies/2013/sectors/education |url-status=live }}{{cite web |title=The World's Most Innovative Companies 2017: Education Honorees |url=https://www.fastcompany.com/most-innovative-companies/2017/sectors/education |access-date=2019-12-14 |website=Fast Company |language=en-US |archive-date=January 10, 2020 |archive-url=https://web.archive.org/web/20200110033354/https://www.fastcompany.com/most-innovative-companies/2017/sectors/education |url-status=live }}{{cite web |title=The World's Most Innovative Companies 2017: Social Media Honorees |url=https://www.fastcompany.com/most-innovative-companies/2017/sectors/social-media |access-date=2019-12-14 |website=Fast Company |language=en-US |archive-date=January 10, 2020 |archive-url=https://web.archive.org/web/20200110033524/https://www.fastcompany.com/most-innovative-companies/2017/sectors/social-media |url-status=live }} Duolingo won Best Education Startup at the 2014 Crunchies,{{cite web |author=Luis |title=Duolingo turns two today! |url=https://www.duolingo.com/comment/3412629 |access-date=2014-11-21 |archive-date=February 19, 2018 |archive-url=https://web.archive.org/web/20180219031308/https://www.duolingo.com/comment/3412629 |url-status=live }}{{Cite web |last=Empson |first=Rip |date=2014-02-12 |title=Fast-Growing Duolingo Caps Off a Big Year with the Crunchie for 'Best Education Startup' |url=https://techcrunch.com/2014/02/11/fast-growing-duolingo-caps-off-a-big-year-with-the-crunchie-for-best-education-startup/ |access-date=2023-10-06 |website=TechCrunch |language=en-US |archive-date=December 16, 2023 |archive-url=https://web.archive.org/web/20231216113924/https://techcrunch.com/2014/02/11/fast-growing-duolingo-caps-off-a-big-year-with-the-crunchie-for-best-education-startup/ |url-status=live }} and was the most downloaded 'education app' in Google Play in 2013 and 2014.{{cite web |author=Abhimanyu Ghoshal |date=2014-12-11 |title=Google Play reveals the most downloaded apps, games and entertainment content from 2014 |url=https://thenextweb.com/apps/2014/12/11/google-play-remembers-year-entertainment/ |url-status=live |archive-url=https://web.archive.org/web/20201129215519/https://thenextweb.com/apps/2014/12/11/google-play-remembers-year-entertainment/ |archive-date=November 29, 2020 |access-date=2014-12-29 |publisher=The Next Web}} In July 2020, PCMag named it "The Best Free Language Learning App".{{cite web |title=Duolingo Review |url=https://www.pcmag.com/reviews/duolingo |access-date=2021-08-26 |website=PCMAG |language=en |archive-date=August 26, 2021 |archive-url=https://web.archive.org/web/20210826005718/https://www.pcmag.com/reviews/duolingo |url-status=live }}

As a company, Duolingo has likewise won several awards and recognitions. In 2015, it was announced as that year's Index Award winner in the Play & Learning category by The Index Project.{{Cite web |title=Duolingo |url=https://theindexproject.org/award/winnersandfinalists/duolingo-index-award-2015-winner-play-learning-category |access-date=2023-10-06 |website=theindexproject.org |language=en |archive-date=November 6, 2023 |archive-url=https://web.archive.org/web/20231106225231/https://theindexproject.org/award/winnersandfinalists/duolingo-index-award-2015-winner-play-learning-category |url-status=live }} It won Inc. magazine's Best Workplaces 2018,{{cite web |title=Duolingo |url=https://www.inc.com/profile/duolingo |access-date=2019-08-01 |website=Inc.com |archive-date=August 1, 2019 |archive-url=https://web.archive.org/web/20190801163729/https://www.inc.com/profile/duolingo |url-status=live }} made Entrepreneur magazine's Top Company Culture List 2018,{{cite web |title=Top Company Cultures of 2018 |url=https://www.entrepreneur.com/top-company-culture |access-date=2019-08-01 |website=Entrepreneur |language=en |archive-date=February 4, 2023 |archive-url=https://web.archive.org/web/20230204065617/https://www.entrepreneur.com/top-company-culture |url-status=dead }} was among CNBC's "Disruptor 50" lists for 2018 and 2019,{{Cite news |last= |first= |date=2018-05-22 |title=2018 Disruptor 50: No. 35 Duolingo |url=https://www.cnbc.com/2018/05/22/duolingo-2018-disruptor-50.html |url-status=live |archive-url=https://web.archive.org/web/20181105202606/https://www.cnbc.com/2018/05/22/duolingo-2018-disruptor-50.html |archive-date=November 5, 2018 |access-date=2018-11-05 |work=CNBC}}{{cite web |date=2019-05-15 |title=Duolingo: 2019 Disruptor 50 List |url=https://www.cnbc.com/2019/05/14/duolingo-2019-disruptor-50.html |access-date=2019-09-04 |website=CNBC |language=en-US |archive-date=October 7, 2019 |archive-url=https://web.archive.org/web/20191007170418/https://www.cnbc.com/2019/05/14/duolingo-2019-disruptor-50.html |url-status=live }}{{cite press release |title=Duolingo Names Gillian Munson to Board of Directors |url=https://www.prnewswire.com/news-releases/duolingo-names-gillian-munson-to-board-of-directors-300931393.html |access-date=2019-12-14 |website=PR Newswire |language=en |archive-date=November 20, 2019 |archive-url=https://web.archive.org/web/20191120154202/https://www.prnewswire.com/news-releases/duolingo-names-gillian-munson-to-board-of-directors-300931393.html |url-status=live |date=October 7, 2019}} and was ranked as one of TIME magazine's 50 Genius Companies.{{Cite magazine |title=Duolingo: The 50 Most Genius Companies of 2018 |url=https://time.com/collection/genius-companies-2018/5412500/duolingo/ |magazine=Time |language=en-us |access-date=5 November 2018 |archive-date=November 8, 2018 |archive-url=https://web.archive.org/web/20181108220506/http://time.com/collection/genius-companies-2018/5412500/duolingo/ |url-status=live }} Duolingo was named one of Forbes{{'s}} "Next Billion-Dollar Startups 2019".{{cite web |last=Feldman |first=Amy |title=Next Billion-Dollar Startups 2019 |url=https://www.forbes.com/sites/amyfeldman/2019/07/16/next-billion-dollar-startups-2019/ |access-date=2019-07-20 |website=Forbes |language=en |archive-date=July 20, 2019 |archive-url=https://web.archive.org/web/20190720195522/https://www.forbes.com/sites/amyfeldman/2019/07/16/next-billion-dollar-startups-2019/ |url-status=live }} In 2023, Duolingo won a Design Award during the 2023 edition of the Apple Design Awards.{{Cite web |last1=T. |first1=Puja |last2=Ghadashi |first2=S. |last3=Sethi |first3=N. N. |date=June 9, 2023 |title=Duolingo wins Apple Design Award for innovation in design |url=https://glamsham.com/world/technology/duolingo-wins-apple-design-award-for-innovation-in-design |url-status=dead |archive-url=https://web.archive.org/web/20231004135637/https://glamsham.com/world/technology/duolingo-wins-apple-design-award-for-innovation-in-design |archive-date=October 4, 2023 |access-date=June 7, 2024 |website=Glamsham}}

File:Duo from Duolingo.svg

Duolingo has brand characters that are used for engagement and creating storylines.{{Cite web |date=2020-11-10 |title=Building character: How a cast of characters can help you learn a language |url=https://blog.duolingo.com/building-character/ |access-date=2024-08-24 |website=Duolingo Blog |language=en}}{{Cite AV media |url=https://www.youtube.com/watch?v=m-3-D7S0piw |title=Creating Our Duolingo Characters • Greg Hartman • Duocon 2020 |date=2020-09-26 |last=Duolingo |access-date=2024-07-24 |via=YouTube}} The main characters include:{{Cite web |date=8 March 2022 |title=How Zari, Bea, Lily, Lucy, and Lin came to life |url=https://blog.duolingo.com/duolingo-female-character-origin-stories/ |access-date=26 September 2024 |website=Duolingo Blog |language=en}} {{Webarchive |url=https://web.archive.org/web/20240311163848/https://blog.duolingo.com/duolingo-female-character-origin-stories/

|date=11 March 2024}} at Duolingo Blog

• Beatrice "Bea" Boateng:{{Cite web |title=Duolingo English Test |url=https://englishtest.duolingo.com/sample_certificate |access-date=2025-02-15 |website=Duolingo English Test |language=en}} Born on January 1, 2000, Bea is a smart and energetic young girl.
• Duo Keyshauna Renee Lingo: Commonly known as Duo or Duo the Owl, he is the company's green owl mascot. On February 11, 2025, Duolingo announced, as part of a publicity stunt, that Duo had died,{{Cite web |last=Bartos |first=Madeline |date=2025-02-12 |title=Duolingo Owl is dead, company says - CBS Pittsburgh |url=https://www.cbsnews.com/pittsburgh/news/duolingo-owl-dead/ |access-date=2025-02-14 |website=CBS News |language=en-US}}{{Cite web |date=2025-02-13 |title=Duo, the Duolingo owl, has 'died' - leaving users in mourning (and somewhat relieved) |url=https://www.independent.co.uk/life-style/duolingo-owl-mascot-death-duo-tribute-dua-lipa-b2697349.html |access-date=2025-02-14 |website=The Independent |language=en}}{{Cite web |last=Booth |first=Callum |date=2025-02-12 |title=Duolingo Owl Dies—But 'The Dead Internet Theory' Lives On |url=https://www.forbes.com/sites/callumbooth/2025/02/12/duolingo-owl-dies-but-the-dead-internet-theory-lives-on/ |access-date=2025-02-14 |website=Forbes |language=en}} after being hit by a Tesla Cybertruck.{{Cite web |last=Hamedy |first=Saba |date=2025-02-12 |title=Duolingo 'killed' off its mascot — and somehow captivated the internet |url=https://www.nbcnews.com/pop-culture/duolingo-death-owl-duo-cybertruck-social-media-what-happened-rcna191939 |access-date=2025-02-15 |website=NBC News |language=en}}{{Cite web |last=Cross |first=Greta |title=Duolingo's make-believe owl mascot Duo dies by Cybertruck in new TikTok |url=https://www.usatoday.com/story/money/2025/02/12/duolingo-duo-owl-dead-cybertruck/78457365007/ |access-date=2025-02-15 |website=USA TODAY |language=en-US}}{{Cite web |last1=Gallaga |first1=Omar |last2=Cooper |first2=Gael |date=2025-02-14 |title=Duolingo Is Selling a Coffin for Dead Mascot Duo the Owl |url=https://www.cnet.com/culture/internet/duo-the-duolingo-owl-cruelly-murdered-by-a-tesla-cybertruck-now-sold-in-coffin-shaped-box/ |access-date=2025-02-15 |website=CNET |language=en}} Later, Duolingo put up a website where the users of the app would have to work together to obtain 50 Billion in-app experience to resurrect Duo.{{Cite web |last=Cross |first=Greta |title=Duolingo's make-believe mascot, Duo the Owl, duped his death |url=https://www.delawareonline.com/story/tech/2025/02/24/duolingo-duo-owl-mascot-faked-death/80059015007/ |access-date=2025-02-25 |website=The News Journal |language=en-US}} After the goal was reached, Duolingo then posted a video on their social medias of Duo's resurrection.{{Cite web |title=Duolingo Resurrects Its Mascot After Viral Cybertruck Death |url=https://www.designrush.com/news/duolingo-resurrects-its-mascot-after-viral-cybertruck-death |access-date=2025-02-25 |website=www.designrush.com |language=en}} The company also stated the character's birth date as 1000BC, and his full name as Duo Keyshauna Renee Lingo.{{Cite web |last=Cross |first=Greta |title=Duolingo announces death of Duo the Owl, its make-believe mascot: 'He had many enemies' |url=https://www.usatoday.com/story/money/2025/02/11/duolingo-duo-owl-death/78425853007/ |access-date=2025-02-14 |website=USA TODAY |language=en-US}}{{Cite web |last=Steinberg |first=Brooke |date=2025-02-12 |title=Duolingo announces the death of its beloved owl mascot, Duo |url=https://nypost.com/2025/02/12/lifestyle/duolingo-announces-the-death-of-its-beloved-owl-mascot-duo/ |access-date=2025-02-14 |website=New York Post |language=en-US}} Duo served as the motivational face of the app, encouraging users to complete their lessons and maintain their learning streaks. Duo has become a well-known internet character, often depicted humorously as aggressively reminding users to not miss their streaks. Over time, Duo has gained a significant reputation in memes for being persistent—even threatening—about keeping users on track with their lessons. According to Duolingo Brand Guidelines, "Duo is a boy" and communicates through text only.{{Cite web |title=Brand Guidelines - Duolingo |url=https://design.duolingo.com/writing/duo#duos-and-duonts |access-date=2025-02-12 |website=design.duolingo.com}}
• Eddy: An optimistic character with a passion for sports, father of Junior.
• Falstaff: An older, intellectual grizzly bear with a love for literature.
• Junior: A curious and eager young boy.
• Lily: A teenage girl known for her sarcastic, emo, and indifferent personality, often expressing a lack of enthusiasm but secretly caring about her friends. She is one of the main characters in Duolingo’s cast of mascots used in video call feature.{{Cite AV media |url=https://www.youtube.com/watch?v=wD1X9hWHm5k&t=4228s |title=Duocon 2022 |date=2022-09-30 |last=Duolingo |access-date=2024-11-25 |via=YouTube}}
• Lin: A creative and adventurous artist and motorcyclist.
• Lucy: A venturesome elderly lady, grandmother of Lin.
• Oscar: A high school teacher and a prim connoisseur of art and culture.
• Vikram: A calm and responsible professional.
• Zari: A confident and enthusiastic Middle Eastern teenage girl. She dresses in pink and blue and wears a headscarf/hijab. She is Lily's best friend.

All characters mentioned above are human, with the exceptions of Duo, who is an owl, and Falstaff, who is a bear.

Due to the app's frequent reminder notifications, Duolingo's mascot, a green cartoon owl named Duo, has been the subject of Internet memes antagonising him, with the character often depicted stalking or threatening users if they do not continue using the app.{{cite web |last=Anderson |first=Sage |title=The Duolingo owl is out for vengeance in these threatening memes. |url=https://mashable.com/article/duolingo-owl-memes/ |access-date=2019-06-07 |website=Mashable |date=2019-03-27 |language=en |archive-date=January 4, 2021 |archive-url=https://web.archive.org/web/20210104162637/https://mashable.com/article/duolingo-owl-memes/ |url-status=live }}{{Cite web |last=Gibbs |first=Alice |date=2023-12-05 |title=Threatening note from the Duolingo owl leaves internet in stitches |url=https://www.newsweek.com/threatening-note-duolingo-owl-internet-stitches-1849686 |access-date=2024-06-25 |website=Newsweek |language=en}}

Duolingo has leaned into its online reputation and has adjusted its social media and marketing strategies accordingly.{{cite web |last1=Bajaj |first1=Sunil |date=November 23, 2023 |title=How a 23-year-old graduate helped transform Duolingo's social media marketing |url=https://www.contagious.com/news-and-views/duolingo-social-media-marketing |access-date=13 April 2024 |website=Contagious |language=en}} Acknowledging the meme, Duolingo released a video on April Fools' Day 2019, depicting a facetious new feature called "Duolingo Push". In the video, users of "Duolingo Push" are reminded to use the app by Duo himself (depicted by a person wearing a Duolingo mascot costume), who stares at and follows them until they comply.{{cite AV media |url=https://www.youtube.com/watch?v=8wc83qX6oNM |title=Introducing Duolingo Push |date=2019-03-31 |publisher=Duolingo |access-date=2019-06-07 |archive-url=https://web.archive.org/web/20230218131458/https://www.youtube.com/watch?v=8wc83qX6oNM |archive-date=February 18, 2023 |url-status=live |via=YouTube}}{{cite web |date=April 30, 2019 |title=How Duolingo Took over the Meme World and What Marketers Can Learn from It |url=https://www.rypl.io/post/what-is-the-duolingo-meme-craze-and-what-marketers-can-learn-from-it |url-status=dead |archive-url=https://web.archive.org/web/20190607075051/https://www.rypl.io/post/what-is-the-duolingo-meme-craze-and-what-marketers-can-learn-from-it |archive-date=June 7, 2019 |access-date=2019-06-07 |website=rypl.io}} It was also acknowledged during Duolingo's 2022 April Fools' Day video, "Lawyer Fights Duolingo Owl for $2,700,000", where a fictitious law firm fights for those that have been harmed by Duolingo's owl mascot.{{cite web |date=April 1, 2022 |title=Lawyer Fights Duolingo Owl for $2,700,000 |url=https://www.youtube.com/watch?v=ga3ttnz3nXI |access-date=13 April 2024 |website= |publisher=Duolingo |language=en |via=YouTube}} This was further referenced by the company in its 2024 April Fools' Day skit "Duo on Ice", in which the owl, in a mix of Spanish and English, admitted to having an appetite for human flesh, and if the user failed to continue their streak, they would "eat their head like a praying mantis."{{cite web |title=Spanish or Vanish (full song) from Duolingo On Ice | date=April 2024 |url=https://www.youtube.com/watch?v=dWXuz95uBQo |access-date=13 April 2024 |publisher=Duolingo |language=en |via=YouTube}} In February 2020, as part of the company's partnership with the developers of the video game Angry Birds 2, a skit depicting Duo and the red Angry Bird attacking a crowd was uploaded.{{Cite youtube |url=https://www.youtube.com/watch?v=P59ceJ7vBLY&ab_channel=Duolingo |title=Duolingo X Angry Birds 2: The Team-Up |date=February 18, 2020 |last=Veselic |first=Ana |last2=Alexander |first2=Anne |last3=Chermayeff |first3=Jessica |last4=Gavazzi |first4=Andrea |last5=Goldberg |first5=Alexander |last6=Marotta |first6=Lily |last7=Register |first7=Julia |type=Trailer |language=en |publisher=Duolingo |via=YouTube}}

Duolingo has effectively engaged with Generation Alpha through its YouTube shorts, featuring global meme trends and content like songs, workplace insights, and humor, including elements of dark comedy, and "kidnapping children" as a joke.{{Cite web |title=Duolingo |url=https://www.youtube.com/@duolingo |access-date=2025-01-31 |website=YouTube |language=en}}

In November 2019, Saturday Night Live parodied Duolingo in a sketch where adults learned to communicate with children by using a fictitious course called "Duolingo for Talking to Children".{{Cite news |last=Lee |first=Madasyn |date=2019-11-05 |title=Pittsburgh-based Duolingo a fan of talk-to-kids 'SNL' sketch |work=Pittsburgh Tribune-Review |url=https://triblive.com/local/pittsburgh-allegheny/pittsburgh-based-duolingo-a-fan-of-snls-talk-to-kids-skit/ |access-date=December 13, 2019 |archive-date=December 13, 2019 |archive-url=https://web.archive.org/web/20191213075049/https://triblive.com/local/pittsburgh-allegheny/pittsburgh-based-duolingo-a-fan-of-snls-talk-to-kids-skit/ |url-status=live }}

The 2023 film Barbie contains a running gag where the husband of disgruntled Mattel employee Gloria uses Duolingo to learn Spanish, Gloria's native language.

Duo's Taqueria is a taqueria (a Mexican taco restaurant) in Pittsburgh, Pennsylvania, operated by Duolingo. The taqueria offers a variety of authentic Mexican tacos and other traditional dishes.{{Cite web |title=Duo's Taqueria |url=https://www.duostaqueria.com/ |access-date=2024-08-24 |website=Duo's Taqueria |language=en-US}} The restaurant encourages patrons to order in Spanish, aligning with Duolingo's mission of making language learning fun and accessible. Duolingo's taco shop brought in $700,000 in 2023.{{Cite web |last=Agarwal |first=Aakanksha |date=2024-06-12 |title=Duolingo's viral taco shop pulls in $700k in first year |url=https://technical.ly/startups/duolingo-restaurant-duos-taqueria-700k-success/ |access-date=2024-08-24 |website=Technical.ly |language=en}}

Duolingo is headquartered in Pittsburgh, Pennsylvania, and has offices in Seattle, New York,{{cite news |last1=Budds |first1=Diana |title=Inside Duolingo's stunning new NYC office, where employees get to choose where and how they work |url=https://www.fastcompany.com/91183352/duolingo-office-nyc-employees-choices-about-how-they-want-to-work |access-date=September 5, 2024 |work=Fast Company |date=September 5, 2024}} Detroit,{{Cite web |last=Perez |first=Sarah |date=2024-07-09 |title=Duolingo acquires Detroit-based design studio Hobbes |url=https://techcrunch.com/2024/07/09/duolingo-acquires-detroit-based-design-studio-hobbes/ |access-date=2024-07-22 |website=TechCrunch |language=en-US}} Beijing, and Berlin.{{Cite web |title=Duolingo Careers |url=https://careers.duolingo.com/#locations |access-date=2024-11-03 |website=careers.duolingo.com |language=en}}

In 2024, Duolingo opened a new office in New York City, featuring an art gallery in which the company's characters are depicted in the style of famous historical paintings. The gallery showcases moving images of Duo and other characters in a range of artistic styles.{{Cite AV media |url=https://www.youtube.com/shorts/JCl8xaXOw44 |title=Inside Duolingo's Stunning New NYC Office: Art Gallery & Innovative Workspaces Revealed! |language=en |access-date=2024-09-07 |via=www.youtube.com}}{{Cite AV media |url=https://www.youtube.com/watch?v=cJJKA1JVY1s |title=Duolingo Opens New Office in NYC |date=2024-09-07 |last=Duolingo Path |access-date=2024-09-07 |via=YouTube}}

Duolingo employs around 830 people.{{Cite web |last=SeanColombo |date=2024-09-27 |title=I'm not sure, we don… |url=https://www.reddit.com/r/duolingo/comments/1foeq6y/comment/lp71ird/?rdt=63886 |access-date=2024-09-28 |website=r/duolingo}}{{Cite web |last=Patel |first=Nilay |date=2024-10-14 |title=Duolingo CEO Luis von Ahn thinks AI has a lot to teach us |url=https://www.theverge.com/24267841/luis-von-ahn-duolingo-owl-language-learning-gamification-generative-ai-android-decoder |access-date=2024-11-02 |website=The Verge |language=en}}

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