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Duolingo collects the most data among language apps

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One of the most popular language learning apps, Duolingo, is at the forefront of collecting user data, with Bussu and iHuman in second and third place, respectively, according to the data collection details on the App Store.

In the wake of recent data leaks, concerns over data privacy within such apps have surged to the forefront of public consciousness, especially when many of us are not privacy-oriented and lack knowledge about this aspect of the cyber world.

The incidents, especially big ones like Duolingo’s data breach of its 2.68 million customers, are a stark reminder that the applications do more than hone our skills; they are also a repository of heaps of our data, which can fall into the wrong hands and shatter our privacy.

Surfshark analysed the data points collected by the language apps and found that Duolingo collects most user data.

The researchers found that Duolingo gathers 19 out of 32 data points, nearly 60% of the available data. The data pertains to name, email address, phone number, physical address, payment information, photos or videos, and search history.

Researchers also found out that out of the 19 unique data points that Duolingo collects, it tracks 13 of them, which is by far the largest.

A comparative analysis of the data points that each language-learning app consumes. | Source: Surfshark

Busuu app comes a close second with 17 collected data points, with Human at the third spot with 12 data points. While Bussu tracks 2 out of 17 data points, iHuman tracks zero.

In contrast, some language-learning apps do follow a privacy-oriented approach. For example, EWA collects only 5 of the 32 data points, HelloTalk captures 7, and Mondly retains 8. HelloTalk, while capturing only 7 data points, does track the precise location of the customers, a feature distant to HelloTalk.

Moreover, the main issue isn’t the data collection; it is about how these apps manage the collected data. Most of these apps use data for tracking and often share it with third-party advertisers and data brokers. On average, these apps use three data points for tracking purposes, although not the precise location but purchase history, course location, and phone number.

Duolingo stands at the top in this regard, too. It uses 13 out of 19 data points to track users.

“Knowing what type of data your beloved language learning app collects can lead to informed decisions regarding its usage,” Surfshark’s lead researcher, Agneska Sablovskaja, told Candid.Technology. “As the new school and work season begins, many people are eager to learn a new language. However, in the pursuit of linguistic skills, it’s easy to overlook a crucial aspect: the data-hungry nature of popular language-learning apps.”

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Kumar Hemant

Kumar Hemant

Deputy Editor at Candid.Technology. Hemant writes at the intersection of tech and culture and has a keen interest in science, social issues and international relations. You can contact him here: