Product-Led Growth in Edtech: The Story of a Top App

The Evolution of Duolingo's Design and Strategy

Luis von Ahn, the CEO and co-founder of Duolingo, felt dissatisfied with the conventional, austere design commonly adopted by edtech companies, which often mimicked traditional universities. He and the initial Duolingo team instead drew inspiration from popular mobile games such as Angry Birds and Clash Royale. Their goal was to create a learning experience that felt more dynamic and engaging than a typical classroom setting.

This creative approach resulted in the company’s iconic mascot: Duo, a playfully rebellious owl rendered in a vibrant evergreen hue.

Rethinking Language Learning for Mobile

Duolingo’s transformation wasn’t limited to aesthetics. The company aimed for a complete overhaul of language learning, specifically tailored for mobile platforms. Traditional, top-down curriculums were replaced with strategies driven by data analytics.

This shift embraced an ethos that has since become known as product-led growth.

Understanding Product-Led Growth

Product-led growth is a strategy employed by companies like Calendly, Slack, and Dropbox. It centers on continuously improving the product itself to cultivate a loyal customer base.

These satisfied customers then organically promote the product to others, creating a self-sustaining cycle of viral growth. This approach is appealing because it significantly reduces user acquisition costs while simultaneously boosting engagement and retention rates.

Duolingo has successfully integrated this model by incorporating engaging elements, moments of enjoyment, and addictive educational features directly into its core application.

Prioritizing Product Development

Early venture capital funding allowed Duolingo to prioritize product development over immediate profitability.

Building on Past Successes

As explored in the first part of this series, von Ahn’s prior work with CAPTCHA technology played a crucial role in Duolingo’s inception. The initial success of crowdsourced translation as a disruptive force in language learning, and the accidental development of a leading education app by interns, provided valuable momentum.

These early achievements fueled the company’s focus on growth, serving two key purposes: validating the effectiveness of their approach and collecting substantial user data to facilitate continuous product iteration and enhance user engagement.

Analyzing Duolingo's Growth Strategy

We will now examine how Duolingo leveraged product-led growth to expand its user base. Furthermore, we will consider how a company founded on gamification strives to strike a balance between playful design and effective educational outcomes.

The Evolution of Language Learning: From Mobile Games to Duolingo's Owl

Following his graduation from an internship at Duolingo – where he contributed to the launch of the company’s iOS application – Tyler Murphy observed a significant shift in the gaming landscape during the mid-2010s. The dominance of titles like Angry Birds was waning as mobile games became increasingly sophisticated. These games incorporated features like in-app purchases, progress indicators, and gameplay designed to be intrinsically motivating.

Murphy began to recognize parallels between the engaging nature of video games and the dedication required for language acquisition. He recalls questioning, “Could learning be structured to increase in difficulty, mirroring a character’s progression in a game?” Duolingo initially drew inspiration from Angry Birds, and later, Clash Royale, which debuted in 2016.

“A substantial portion of the Duolingo team was actively playing Clash Royale at one point,” Murphy stated. “This widespread engagement profoundly influenced our product development and design principles.”

Murphy’s personal experiences also fueled this shift. Having initially pursued a career in Spanish education, he found it challenging to effectively motivate students in a traditional classroom setting.

The understanding that Duolingo could integrate elements from gaming, rather than adhering to conventional edtech approaches, provided a surge of inspiration and empowered the team to explore innovative learning methodologies.

Skill Trees and the Core Duolingo Experience

Fundamental to most games is a system of experience points and leveling. For Duolingo users, this progression is manifested through skill trees.

These trees, originally developed by a design agency during Duolingo’s formative years, represent the central learning experience. They visually map out interconnected language skills that become progressively more challenging and nuanced. Mastering one skill often unlocks access to the next.

The relationships between skills are often logical; for example, discussing restaurants necessitates the ability to introduce oneself. However, some connections represent essential foundational knowledge – understanding daily routines requires familiarity with basic everyday actions.

Within Duolingo, each unit comprises a series of skills, each further divided into five lessons. Successful completion of all five lessons allows a learner to advance to the next skill. Completing all skills within a unit then enables progression to the subsequent unit.

The number of skills varies by language, but users typically encounter around 60 skills distributed across nine units in a single course.

The Impact of a Cartoon Owl Meme on Growth

Duolingo had already established a successful “leveling up” system within its application. However, the next step involved integrating gamification comprehensively throughout the entire user experience. A key challenge was recreating the emotional connection between teacher and student, a vital component for maintaining learner motivation.

Recognizing that failure is universally disliked, Duolingo discovered a scalable solution through its cartoon owl mascot, Duo. This mascot was developed by the same design agency responsible for the app’s skill trees.

Today, users are frequently met with encouragement or gentle reprimands from Duo following their lesson attempts. The design team deliberately incorporated Duo throughout the product, drawing inspiration from Super Mario Brothers as a model for utilizing iconic imagery to foster a welcoming gaming atmosphere.

Initially, Duo’s presence was largely static, functioning more as an icon than a fully developed character. This changed as the company intensified its focus on user engagement.

Duolingo is well-known for its consistent and assertive daily push notifications, designed to encourage app usage. Artificial intelligence and sophisticated algorithms are employed to select from a vast library of potential reminders and messages, aiming to maximize engagement and, often, to motivate users through a sense of obligation, frequently delivered with Duo prominently featured.

While these notifications prove effective, users quickly identified an opportunity to playfully critique the sometimes-passive-aggressive tone of the messages. As the app’s popularity grew and Duo’s presence became increasingly pervasive, users responded predictably by creating memes depicting Duo threatening them to continue their language learning.

When these memes began to circulate, Murphy noted an initial conflict with Duolingo’s commitment to consistent branding and its aspiration to become an iconic brand. However, the burgeoning meme and remix culture also presented a potential opportunity rather than simply a controversy.

“It was the emergence of the memes that prompted us to intentionally showcase Duo’s full spectrum of emotions,” Murphy explained. “We decided to portray him as angry, and to explore other emotions typically avoided in branding. The memes essentially gave us the go-ahead to amplify what users were already creating.”

Now, correct answers are often met with a celebratory dance from Duo. Conversely, a missed practice day might trigger a screen appearance from Duo displaying pleading, puppy-dog eyes.

https://twitter.com/lazycamgirl/status/1322610979532808192

Duo and the push notifications even served as the basis for a 2019 April Fool’s Day prank: users could “hire” Duo to physically motivate them to practice a language. A dedicated page now showcases Duo fan art, and Duo is available as a filter on Instagram.

More recently, Duolingo expanded its character roster, introducing a variety of new characters to foster user attachment. This addition of character and cultural elements further strengthens the emotional connection initially established with Duo.

The Duolingo Universe draws inspiration from the Super Mario Brothers franchise. This strategic crossover, mirroring techniques used in gaming and film, has significantly contributed to Duolingo’s success and represents a consistently high-performing product growth strategy.

Gamification Strategies in Duolingo: Leaderboards, Streaks, and Hearts

Duolingo has successfully integrated elements commonly found in video games to boost user engagement, improve retention rates, and ultimately, facilitate language acquisition within its application.

For instance, leaderboards allow users to compete with peers of comparable skill levels globally. Beginners learning Spanish are matched against other Spanish beginners, with higher experience points translating to a better position on the board. This taps into a fundamental human desire for competition, as highlighted by a Twitter user:

https://twitter.com/cescaventaniIIa/status/1382991419925798912

Luis von Ahn, the founder, stated that leaderboards increased time spent on the app by 20%. He noted that approximately half of all users are motivated by competition, and this feature significantly influences their activity. It’s a remarkably effective persuasive tool.

While beneficial for growth, the introduction of competition into learning environments is a topic of debate among educators, who often prioritize inclusivity over a system that inherently creates winners and losers.

Another key feature is the implementation of streaks, visually representing the number of consecutive days a user completes at least one lesson. Duolingo’s push notifications are frequently centered around maintaining these streaks, enhancing engagement for a substantial user base.

Similar to features in Apple Watch, Snapchat, and the NYT Crossword app, streaks leverage the human need for validation and the satisfaction of tracking progress. Receiving rewards for consistent effort is highly motivating, and conversely, losing a streak can evoke feelings of disappointment. To mitigate this, Duolingo introduced lingots, an in-app currency used to purchase power-ups, including streak freezes to protect against missed days.

Duolingo reports that over 50% of its active users maintain a streak of at least seven days.

Beyond boosting engagement, streaks also contribute to organic, viral growth. Users frequently share their milestones – such as reaching 100 or 1000-day streaks – on social media, generating authentic attention and free advertising. This leverages the “fear of missing out” (FOMO) effect.

Although streaks excel at driving engagement, their direct educational value is less clear. They can encourage consistent practice, but the depth of that practice is questionable. Completing a single, quick lesson is sufficient to maintain a streak, potentially prioritizing habit formation over genuine language comprehension. Duolingo may be adept at fostering a Duolingo habit, but not necessarily language mastery.

Users have the option to disable leaderboards and streaks, however, a third engagement strategy is more difficult to avoid.

Drawing inspiration from the Zelda game series, Duolingo employs a system of hearts, representing “lives.” Users begin each day with a limited number of hearts, losing one for each mistake. Depleting all hearts temporarily restricts access to lessons. This feature encourages focused attention during lessons, mirroring the consequences of errors in traditional assessments. Consistent errors lead to penalties and potential streak loss, aiming to improve comprehension and add an element of challenge.

Karin Tsai, an early Duolingo engineer, acknowledged that hearts are the company’s most debated feature. She questioned the logic of penalizing users for making mistakes, a natural part of the learning process. Some educators actively encourage errors as learning opportunities, while Duolingo restricts access upon repeated mistakes.

Despite potential discrepancies between traditional pedagogy and Duolingo’s growth tactics, there is a degree of convergence. Duolingo consistently emphasizes that learning is a beneficial habit.

“We hope that this is the one game that you are okay being addicted to because it is good for you,” stated Murphy. “We try to make sure the things we get you hooked onto are aligned to the things that have the highest learning value.”

A/B Testing in Product Development

A/B testing, a methodology brought to prominence by Optimizely of San Francisco, involves presenting different versions of a product to distinct user groups. This allows for the assessment of user responses to each variation.

This approach is particularly favored during the beta phase of new features or products for startups. Rather than developing without clear direction, developers can refine their offerings based on user preference. For instance, a newsletter platform might experiment with two different headlines, tracking click-through rates to determine the most effective option for broader distribution.

Duolingo exemplifies a company that heavily utilizes A/B testing, given its reliance on subtle and impactful gamification. The company consistently and quickly evaluates various features, often with as many as 100 tests running concurrently. To facilitate this, Duolingo’s analytics team has created a dashboard that generates nightly reports detailing the impact of each experiment.

Strategic Course Selection for Testing

Duolingo employs a specific strategy when introducing new features. Typically, these features are initially tested within the French course for English speakers. This allows the team to achieve statistical significance more rapidly due to the course’s high user volume.

While the Spanish course for English speakers is even more popular, the team deliberately avoids testing within it. The concern is that the presence of many fluent Spanish speakers among Duolingo’s product staff could introduce bias into the A/B test results.

Localization and Global Considerations

Although many product changes are implemented globally, Duolingo recognizes the importance of localization when scaling a language-learning application internationally.

For example, in China, the app requests users’ phone numbers instead of email addresses, reflecting local communication preferences. Similarly, a technical issue in India prevented users from accessing English courses designed for Hindi speakers, a problem that was subsequently resolved.

Furthermore, the company prioritizes minimizing app latency to ensure optimal performance in developing nations. This focus is crucial for providing a seamless user experience across diverse geographical locations.

• A/B testing allows for data-driven product decisions.
• Duolingo utilizes a large number of concurrent tests.
• Strategic course selection impacts testing efficiency.
• Localization is vital for global app performance.

Establishing Boundaries for Change Implementation

Leaders in product development are encouraged to experiment with new features and modifications, however, Duolingo operates with a defined set of guardrail metrics. These are key indicators that the company aims to maintain or improve upon during the introduction of any new functionality. These metrics encompass user retention rates, daily active users in non-English-speaking regions, and application latency.

Clearly defining these guardrails ensures Duolingo’s team members avoid unintentionally impacting crucial performance indicators while focusing on other objectives.

All startups inevitably face trade-offs, prioritizing certain opportunities over others. For Duolingo, this often involves balancing educational value with user engagement, or vice versa.

“Our goal is to deliver an experience that not only makes users highly proficient in a language, but also meets their expectations for enjoyment and convenience,” explained Tsai. “Achieving a balance between effectiveness and engagement is a continuous challenge.”

While user retention is demonstrably successful for Duolingo, surpassing many competitors in terms of consistent user return, it doesn’t equate to genuine learning effectiveness. The reality is that many individuals lack the inherent drive, motivation, or cognitive ability to benefit from bite-sized lessons, even with consistent participation.

Tsai acknowledges that Duolingo dedicated considerable time attempting to identify a single metric that could comprehensively measure both learning comprehension and user engagement.

“Previously, we were hindered by the belief that such a metric was essential for progress,” Tsai stated. “Ultimately, what allowed us to move forward was accepting that we couldn’t wait indefinitely for a definitive learning metric.”

The inability to rely on a single, all-encompassing learning metric complicates the balancing act. Even with features designed to be both engaging and educational, the more easily measurable outcome will naturally receive greater emphasis.

Duolingo’s success in creating a highly addictive, free application is attributable to its mascot, gamification elements, and a robust testing methodology. However, as the platform expands, the associated pressures evolve. Rapid user growth necessitated a strategy for sustaining Duolingo’s core mission.

The influx of new users placed a significant financial strain on the company, requiring approximately $42,000 in daily expenditures for servers, personnel, and operational costs.

Von Ahn’s initial promise at launch began to show its limitations: “No advertisements, no concealed charges, no subscriptions – simply free,” the promotional trailer proclaimed. Five years later, Duolingo would implement many of these previously excluded practices, a topic we will explore in the next section of this EC-1.

Duolingo EC-1 Contents

• Introduction
• Part 1: Founding Story
• Part 2: Product-Focused Growth Strategy
• Part 3: Revenue Generation
• Part 4: Recent Developments and Future Prospects

Additional EC-1 analyses are available on Extra Crunch.

Updated on May 3, 2021: The Skill Tree was developed by Luis and the initial Duolingo design team, not an external design agency as previously reported.