Duolingo logo, featuring the mascot Duo
|Slogan||"Free language education for the world"|
Type of site
|Online education, Translation, Crowdsourcing|
|Launched||30 November 2011|
|1,719 (April 2015[update])|
Duolingo // is a free language-learning platform that includes a language-learning app along with a crowdsourced text translation platform, and a language proficiency assessment center. Duolingo is ad-free and users are not charged for its services. The language-learning app offers over 40 different language courses across 23 languages, and is available on the Web, iOS, Android and Windows Phone 8.1 platforms with over 100 million registered users across the world.
The project was started in Pittsburgh by Carnegie Mellon University professor Luis von Ahn (creator of reCAPTCHA) and his graduate student Severin Hacker, and then developed along with Antonio Navas, Vicki Cheung, Marcel Uekermann, Brendan Meeder, Hector Villafuerte, and Jose Fuentes. The project was originally sponsored by Luis von Ahn's MacArthur fellowship and a National Science Foundation grant. Additional funding was later received in the form of investments from Union Square Ventures and actor Ashton Kutcher's firm A-Grade Investments.
Duolingo started its private beta on 30 November 2011 and accumulated a waiting list of more than 300,000 users. On 19 June 2012, Duolingo launched for the general public. Due to popular interest, Duolingo has received many investments including $20 million Series C round of investment led by Kleiner Caufield & Byers. Duolingo has 42 staff members, many who were Google employees, and operates from an office in the Pittsburgh neighborhood of Shadyside near Carnegie Mellon's campus.
On 13 November 2012 Duolingo released their iOS app through the iTunes App Store. The application is a free download and is compatible with most iPhone, iPod and iPad devices. On 29 May 2013, Duolingo released their Android app, which was downloaded over a million times in the first three weeks and quickly became the #1 education app in the Google Play store. Duolingo then released both a Google Glass App (glassware) and support for Android Wear.
Duolingo is ad-free and single users are not charged for its services. To earn money, Duolingo employs a crowd sourced business model, where members of the public are invited to translate content and vote on translations. The content comes from organizations that pay Duolingo to translate it. Documents can be added to Duolingo for translation with an upload account which must be applied for. On 14 October 2013, Duolingo announced it had entered into agreements with CNN and BuzzFeed to translate articles for the companies' international sites. In July 2014, Duolingo started a language certification service as a new business model (see #Duolingo Test Center).
Venture capitalists and investment firms that hold a stake in Duolingo include Fred Wilson, New Enterprise Associates, Google Ventures, Union Square Ventures, and Ashton Kutcher's firm A-Grade Investments.
Duolingo provides extensive written lessons and dictation, with speaking practice for more advanced users. It has a gamified skill tree that users can progress through and a vocabulary section where learned words can be practiced.
Users gain "experience points" (XP) as they learn a language, such as when they complete a lesson. Skills are considered "learned" when users complete all the lessons associated with the skill. Users win one point for each correct answer, and lose one for each error, and validate the lesson when they reach 10 points. (In an earlier version, users used to start with four "lives" on early lessons and three on later lessons, a "life" being lost with each mistake.)
Duolingo also includes a timed practice feature, where users are given 30 seconds and twenty questions and awarded a skill point and seven or ten additional seconds (time depends on the length of the question) for each correct answer. As the goal of Duolingo is to get people to learn the language, each skill (containing between 1 to 10 lessons) has a "strength bar" that corresponds to the computer's estimate of how strongly certain words or constructions still exist in the user's memory. After a certain duration of time, strength bars fade, indicating a need for a user to refresh/re-study that lesson, or to "strengthen weak skills." Courses can teach upwards of 2,000 words. Duolingo uses a data-driven approach to lesson planning. At each step along the way, the system measures which questions the users struggle with and what sorts of mistakes they make.
The efficacy of Duolingo's Spanish course has been reviewed by an external study commissioned by the company. Conducted by professors at City University of New York and the University of South Carolina, the study estimated that 34 hours on Duolingo may yield reading and writing ability of a US first-year beginners' course college semester, which takes in the order of 130+ hours. The research did not measure speaking ability. It found that a majority of students dropped out after less than 2 hours of study. The same study found that Rosetta Stone users took between 55 and 60 hours to learn a similar amount.
Instead of slowly adding additional languages, CEO Luis von Ahn announced on 29 May 2013 that they would create the tools necessary for the community to build new language courses, with the hope to introduce more languages and "empower other experts and people passionate about a specific language to lead the way". The result was The Language Incubator, which was released on 9 October 2013. In addition to helping the community create courses for widely spoken languages, the Duolingo Incubator also aims to help preserve some of the less popular languages such as Latin, Mayan and Basque. The first course entirely created by the Duolingo community through the Incubator was learning English from Russian, which launched in beta on 19 December 2013. Other courses created by the Duolingo community include English from Turkish, Dutch and Hungarian, as well as French and Portuguese from Spanish.
The Incubator has three Phases. First, when sufficient interest to contribute to a new course has been received from volunteers fluent in both languages (a requirement for application), the course begins in "Phase 1: Not Yet Released," . The second phase, "Phase 2: Released in Beta," begins when the course has been fully prepared and is ready for open beta testing. Finally, "Phase 3: Graduated from Beta" is when a course is considered relatively stable. The reason complete courses remain in the Incubator is that Moderators/Contributors can continue to improve the course. For example, if a student gets a question wrong but notices there was an error on the program's behalf, which either misled the student or counted a correct answer wrong, they may submit a report detailing what happened.
Courses from/ in English
As of 28 May 2015[update], 13 courses were available to the public from/in English:
10 courses for English speakers are currently in development (ordered by progression percentage towards completion):
Usually, a course teaching English from another language will be made before the reverse (a course teaching that language for English speakers). Once that course reaches Phase 3, the course for English speakers is started, presumably with much of the work already done. Exceptions to this rule happen when a language has few speakers and/or most speakers already know English, e.g. Irish.
Duolingo Test Center
Duolingo launched Duolingo Test Center on 22 July 2014. It is an online language certification platform that can be taken on the Web, iOS or Android, where tests are proctored through microphone and camera. The test requires 20 minutes to finish, costs 20 USD, and is graded within 48 hours on a scale between 0 and 10. According to a study conducted by University of Pittsburgh, there is a substantial correlation between the scores from Duolingo Test Center and TOEFL iBT.
oDesk adapts the Test Center score as one of their official qualifications with which freelance workers can prove their English fluency. Duolingo collaborates with LinkedIn to allow the score to be easily incorporated into a user's résumé page. Duolingo is working with twelve US universities, including Carnegie Mellon University, to study if the score can be reliably used as one of their admission qualifications.
Duolingo for Schools
Duolingo has been used in schools. For example, in Costa Rica and Guatemala, Duolingo has been used in public schools as a pilot project run by the government.
In January 2015, Duolingo released Duolingo for Schools, to provide teachers with a centralized dashboard that can display their students’ progress. The dashboard helps teachers understand each individual student's weaknesses and strengths at each skill, and helps them optimize their language-teaching methods.
Duolingo uses many services in the Amazon Web Services suite of products, including Amazon DynamoDB, Amazon Virtual Private Cloud, nearly 200 virtual instances in Amazon Elastic Compute Cloud (EC2), Amazon Simple Storage Service (S3) and Amazon Relational Database Service (RDS). The server backend is mainly written in the programming language Python, and the frontend in Backbone.js and Mustache. Duolingo provides a single page web application for desktop computer users and also smart phone applications on Android (both Google Play Store and Amazon Appstore), iOS (App Store) and Windows Phone platforms. 20% of traffic comes from desktop users and 80% from mobile app users.
Recognition and awards
In 2013, Apple chose Duolingo as its iPhone App of the Year, the first time this honor was awarded to an educational application. Also, Duolingo won Best Education Startup at the 2014 Crunchies, and was the most downloaded app in the Education category in Google Play in 2013 and 2014.
- Unofficial Duolingo Wiki
- Computer-assisted language learning
- Language education
- Language pedagogy
- List of language self-study programs
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