Duolingo

Duolingo offers courses on music, math, and 43 languages, ranging from English, French, and Spanish to less commonly studied languages such as Welsh, Irish, and Swahili. Other services include the Duolingo English Test (DET), an online certification program, and Duolingo ABC, a literacy app for children. The company uses a freemium model, with its optional premium service, Super Duolingo, being ad-free and offering more features.

Duolingo, Inc.

Duolingo home page visited while logged out in March 2024
Type of business	Public
Traded as	Nasdaq: DUOL (Class A) S&P 400 component
Founded	2011; 13 years ago (2011)
Headquarters	Pittsburgh, Pennsylvania, U.S.
Area served	Worldwide
Founder(s)	Luis von Ahn Severin Hacker
CEO	Luis von Ahn
Industry	Online education
Products	Duolingo Duolingo ABC Duolingo English Test Duolingo Math
Services	Language, music, and mathematics courses and tests.
Revenue	US$531 million (2023)
Operating income	US$−13 million (2023)
Profit	US$16.1 million (2023)
Total assets	US$954 million (2023)
Total equity	US$656 million (2023)
Employees	≈ 720 (December 2023)
URL	duolingo.com
Advertising	Yes
Registration	Yes
Users	88.4 million MAU (Q4 2023)
Launched	November 27, 2011; 12 years ago (2011-11-27) (private beta) June 19, 2012; 11 years ago (2012-06-19) (public release)
Current status	Online
Native client(s) on	Android, iOS

As of January 2024^[update], Duolingo was the world's most popular language learning app based on monthly downloads, with around 16.2 million users downloading it that month. A systematic review of research on Duolingo from 2012 to 2020 found comparatively few studies on the platform's efficacy for language learning, but the review identified several studies that reported relatively high user satisfaction and enjoyment and positive perceptions of the app's effectiveness.

Early history

The idea for Duolingo was formulated in 2009 by Carnegie Mellon University professor Luis von Ahn and his Swiss-born post-graduate student Severin Hacker. Von Ahn had sold his second company, reCAPTCHA, to Google and, with Hacker, wanted to work on an education-related project. A driving motivation was Von Ahn's upbringing in Guatemala, where he saw how expensive it was for people in his community to learn English. Hacker (co-founder and current CTO of Duolingo) believed that "free education will really change the world" and wanted to provide an accessible means for doing so. In recognition of his contributions to language-learning and technological development, he was recognized by the National Inventors Hall of Fame.

The project was originally financed by Von Ahn's MacArthur fellowship and a National Science Foundation grant. 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.

Funds

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. Duolingo launched a private beta on November 27, 2011, and accumulated a waiting list of more than 300,000 people. It launched to the general public on June 19, 2012, at which point the waiting list had grown to around 500,000.

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. In November 2012, Duolingo released an iPhone app, followed by an Android app in May 2013, at which time Duolingo had around 3 million users. By July 2013, it had grown to 5 million users and was rated the No. 1 free education app in the Google Play Store.

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. 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, it 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. In April 2016, it was reported that Duolingo had more than 18 million monthly users.

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. It was reported that Duolingo had 95 employees. Funds from the Series E round would be directed toward creating initiatives such as a related educational flas app, TinyCards, and testbeds for initiatives related to reading and listening comprehension. On August 1, 2018, Duolingo surpassed 300 million registered users.

In December 2019, it was announced that Duolingo raised $30 million in a Series F funding round from Alphabet's investment company, CapitalG. 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. 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.

Features and media

In October 2013, Duolingo launched a crowdsourced language incubator. In March 2021, it announced that it would be ending its volunteer contributor program and donating money to its volunteer contributors who helped develop it. The company said that from now on, language courses would be maintained and developed by professional linguists aligning with CEFR standards. On June 28, 2021, Duolingo filed for an initial public offering on NASDAQ under the ticker DUOL. From August 2021 to June 2022, the Duolingo language learning app was removed from some app stores in China.

In the early-2020s, Duolingo was noted for its viral videos on the social media platform TikTok.

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. CEO Luis von Ahn stated that there were no plans to reverse the changes—intended to simplify Duolingo for its new users—maintaining both the old and new versions would be difficult. 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. In October 2023, Duolingo released math and music courses in English and Spanish for iOS users.

In March 2023, Duolingo officially announced the planned Duolingo Max, a subscription tier above Super Duolingo, in their blog. In July 2023, Duolingo launched a feature using the iOS widget feature. In January 2024, after having laid off around ten percent of its contractors, Duolingo began using artificial intelligence (AI) to replace tasks usually done by its contractors. In March 2024, the widget feature was also on Android.

Duolingo

Duolingo is an app and website that uses a gamified approach to language learning, with lessons that incorporate translating, interactive exercises, quizzes, and stories. It also uses an algorithm that adapts to each learner and can provide personalized feedback and recommendations. It offers podcasts in some languages, consisting of stories usually told by native speakers in the target language. The programs use simplified grammar and vocabulary, slower intonation, and occasional assistance with context and explanations of words.

Duolingo has been through many design phases. Formerly, it provided users with different "skills" placed along a "tree", where they could progress by completing every skill above them. The user could upgrade the skill at any time, with the final goal of turning it "golden" or "legendary". In November 2022, Duolingo switched to an AI-assisted path, where the user's learning level is put on a single "path", including the stories. After its switch to this new format, it removed the audio-only lessons it had offered for some languages. Duolingo also provides a competitive space, such as in Leagues, where people can compete against their friends or see how they compare with randomly selected worldwide player groupings of up to 30 users. Rankings in Leagues are determined by the amount of "XP" (experience points) earned in a week. Badges in Duolingo represent achievements earned from completing specific objectives or challenges.

Duolingo provides features that allow teachers to track their students' progress.

Duolingo currently offers the following language courses:

 

Duolingo has a widget feature on iOS and Android. The widget feature initially started as Duolingo's annual hackathon project. The iOS widget has 39 illustrations designed by Kyle Ruane that were intended to be another daily reminder to complete lessons. On the top part of the widgets is the users' daily streak. On the Duolingo Blog, they wrote that they "decided to come up with a series of illustrations that would show Duo’s mood at different parts of the day". Any lesson completed in Duolingo will count towards the users' daily streak. The daily streak's visual symbol in Duolingo is fire.

Subscriptions

Most of Duolingo's language-learning features are free, with periodic advertising in its mobile and web browser applications, which users can remove by paying a subscription fee or promoting referral links. This program, known as Super Duolingo, includes benefits such as unlimited hearts (retries), level-skipping, no ads, and progress quizzes.

Duolingo Max is a subscription above Super Duolingo. It uses GPT-4 for its features: Role Play, an AI conversation partner, and Explain My Answer, which breaks down the rules with a modified GPT-4 when the user makes a mistake. It is available on the iOS version of the Duolingo app in Australia, Canada, Ireland, New Zealand, the United Kingdom, and the United States in French and Spanish for English speakers. It was intended for immersion—as in "to have a free-flowing conversation".

Duolingo ABC

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 and Spanish.

Duolingo Math

Duolingo Math is a course for learning elementary mathematics. It is currently only available on iOS devices in English and Spanish.

Duolingo Music

In March 2023, Duolingo was reportedly developing a new music course that would allow users to learn how to read and play music through its gamified learning experience. On October 11, 2023, Duolingo formally unveiled Duolingo Music in a YouTube Short, a new platform within the existing app that provides basic music learning through piano, drums, and sheet music lessons. As of April 2024, it is currently only available on iOS devices.

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 is adaptive, with the questions automatically adjusting to the test-takers' ability level.

Duolingo had revenue of $1 million in 2016, $13 million in 2017, $36 million in 2018, and $250.77 million in 2021. In May 2022, it was reported that 6.8% of its monthly active users paid for the ad-free version of the app. Duolingo has derived most of its revenue from subscriptions, advertising, and its Duolingo English Test. In April 2020, it passed one million paid subscribers; it reached 2.9 million in March 2022, and 4.8 million at the end of March 2023.

Effectiveness

A 2017 study found no significant difference between elementary students learning Spanish through the "gamification" of Duolingo and those learning in classroom environments, with both groups demonstrating a similar increase in achievements and self-efficacy.

A 2022 study on adults using Duolingo as their only language learning tool, published in the journal Foreign Language Annals, found that the participants that 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. Another 2022 study of Malaysian students learning French, published by the National University of Malaysia Press, found that it facilitated the acquisition of vocabulary and concluded that it was "well suited" for beginners in this regard.

Criticism

Some language professionals have criticized its app for its limitations and gamified design. Others have pointed out that Duolingo and similar apps can be a starting point but lack the human interaction required to be fluent in a language and for real-life conversations. Players have also reported that "gamification" has led to cheating, hacking, and incentivized game strategies that conflict with actual learning.

Since the end of October 2023, Duolingo has decided to stop updating its Welsh course to "focus on languages in higher demand". Some users criticize this decision because it came at the expense of learners of a language with limited resources on the market. Some of the Welsh Duolingo contributors have turned to Memrise' "community courses".

Awards

In 2013, Apple chose Duolingo as its iPhone App of the Year, a first for an educational application. That year, Duolingo ranked No. 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". Duolingo won Best Education Startup at the 2014 Crunchies, and was the most downloaded 'education app' in Google Play in 2013 and 2014. In July 2020, PCMag named it "The Best Free Language Learning App".

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. It won Inc. magazine's Best Workplaces 2018, made Entrepreneur magazine's Top Company Culture List 2018, was among CNBC's "Disruptor 50" lists for 2018 and 2019, and was ranked as one of TIME magazine's 50 Genius Companies. Duolingo was named one of Forbes' "Next Billion-Dollar Startups 2019".

 

Due to the app's frequent reminder notifications, Duolingo's mascot, a green cartoon owl named Duo, has been the subject of Internet memes where the mascot is "evil" and stalks and threatens users if they do not keep using the app—with the tongue-in-cheek threat indicating physical harm to the user and/or their family for failing to continue their lesson streak, such as "Spanish or vanish", "French or the trench", and "Japanese or no knees", along with threats to kidnap the user's family and hold them hostage until they resume lessons lest they were executed.

Duolingo has leaned into its online reputation and has adjusted its social media and marketing strategies accordingly. 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. Also acknowledged during Duolingo's 2022 April Fools' Day "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. 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."

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".

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.

• Computer-assisted language learning
• Language education
• Distance education
• Language pedagogy