Skip to main content

Duolingo, an app for learning languages

Download a PDF version of this article (pdf), File Download

Duolingo ( is a web-based language programme that aims to teach languages through a sequence of online tasks. As well as a web-based site there is an app available for Android, iOS and Window-based mobiles. Its manifesto aims to allow access to free language education with no hidden fees, which is the case for the main site and the Duolingo app.  For English language learners, there are two further apps available that solely concentrate on English testing, both of which require a fee.

As most of the activities are around translation, the languages available vary according to the student’s native language. For an English speaker there are an impressive twenty-seven different languages available in the current portfolio/version.  Duolingo not only concentrates on the most widely spoken languages, but includes less far-reaching languages such as Welsh, Dutch, Vietnamese, Esperanto and even Klingon.  Although English is the only option for speakers of some of the languages, some of the possible combinations are very interesting, offering Spanish speakers the option to learn Guaraní.

Both the website and mobile application are ad-free and very well designed, using basic colours and user-friendly menus which are very easy to navigate.  The mobile app requires users to register and create a profile to monitor progress. Your profile sets a daily goal that can be personalised, and encourages you to share your progress by inviting friends to compete with you to keep the learner motivated. The final touch of the profile-setting process in the app allows you to establish a practice reminder every day on your phone. Non-beginners will be asked to try “a placement test” that only takes around 15 minutes to complete and will place you at the start of your learning path.

Each of the levels consists of different units organised either grammatically  (basics, adverbs, past. per.) or by topic (feelings,  sport, nature), both of which are described as “skills” on the site. The activities in these units are mainly based on sets of words and sentences translated into other languages. ”.  The activities in these units are mainly based around translation, matching up and listening exercises, which constrain the construction of meaning due to the limitations of automated scoring. Depending on previous answers, an algorithm determines on which items the student will be tested.

In spite of the positive move to include listening and speaking activities, the automatized pronunciation exposes learners to a monotonous and inconsistent intonation. Furthermore, structures and vocabulary are mainly focused on Peninsular Spanish,  despite the majority of Spanish speakers being geographically located in South and Central America.

After completing each “skill” students earn two ”lingots”.  These are a currency-like reward that students attain for their accomplishments. Inviting friends to Duolingo, translating documents or completing your goal for 10 successive days, amongst others, will give you additional lingots which can also be donated.  Lingots can be used to gain access to Bonus Skills activities, which include learning about culture, idioms and proverbs. After completing a series of skills, checkpoints are greyed out to highlight that the student has reached a certain level.

Whilst Duolingo quantifies fluency (via another algorithm) and offers the possibility to add a badge to your LinkedIn Profile, levels are not mapped on an easily interpretable model,  so there is no clear correlation between Duolingo levels and the Common European Framework of Reference for Languages (CEFR) or any other frameworks to that purpose, making it difficult to ascertain the level achieved.

One of the most important shortcomings of a web-based platform to learn languages is the lack of opportunity to engage in interactive conversation. Over the last 40 years of research in language learning and teaching the central focus of second language instruction has been to prepare learners to use the target language in order to communicate with other speakers of that language. Duolingo’s section “bots” is an attempt to use the language interactively in a conversation. In this section, you hold a real-life conversation with a “bot” (virtual tutor with different roles, changed over time). This section presents the expected constraints of an automated conversation, where the app recognises as you type that the exchange is not going towards the expected response. At this point a “help me answer” menu appears and gives you a clue as to what to ask or talk about next.

According to Vesselinov and Grego’s Duolingo effectiveness study in 2012, more than a third of students were satisfied with their results. Although this is an impressive figure, a high number of learners stopped using the website at an early stage for unknown reasons.  Furthermore, learners with a high level of competency in the target language were excluded from the experiment. This clearly reflects the abovementioned constraints that an online platform poses when using language interactively.

Duolingo’s goal is “to give everyone access to a private tutor experience through technology”. This is certainly the first impression for beginners or intermediate students as, within seconds of registering, there is immediate access to a plethora of activities which helps the learner utilize a limited number of structures and vocabulary of the language they are studying.  However encouraging this might be for learners at an early stage of the learning process, this is definitely not the case for more advanced students that may feel frustrated by the limitations that the platform presents. In whichever case we have to be extremely cautious when evaluating the long-term effectiveness of such platforms. More research is needed to fully assess the educational value of this type of online applications.


Krashen, S. 1982. Principles and Practice in Second Language Acquisition. New York: Prentice Hall.

Vesselinov, R. and Grego, J. 2012. Duolingo effectiveness study. Final Report. [last accessed 12 October 2016]