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Duolingo, the language-learning app, has been using artificial intelligence to create personalised educational experiences for its users for many years. Through its AI system, called Brainbird, Duolingo analyses how users interact with the app and identify areas of strength and weakness. This allows the Duolingo app to adjust lessons and exercises to make the experience more engaging and efficient, resulting in a more personalised experience for each user.

And it's paying off!

Duolingo generated sales of $369 million revenue in 2022, a 47% year-on-year increase over 2021. The language learning app has over 500 million registered users brushing up their language skills in 38 different languages.

Here's The Thing: Duolingo’s goal is to make learning fun and accessible to everyone. They're using AI to do that. This is how they build brand loyalty and enhance customer engagement using emerging technologies.

Now they've integrated OpenAI's GPT-4 to take the Duolingo AI system to the next level.

In these week's Premium content, I explain:

  • the how, why and what of Duolingo's use of AI to build better customer engagement.
  • Duolingo's brand strategy for building loyalty amongst its customers and personalise the user experience using technology.
  • Provide multiple examples of other consumer brands deploying AI to enhance consumer engagement.


Emerging Tech Use-Case: How Duolingo use AI for personalised customer engagement

The Origins of Duolingo: Duolingo, launched in 2012 by Luis von Ahn and Severin Hacker, aims to mimic the supercharging effect of individually tutored lessons using machine learning and other technologies. Duolingo automates three key attributes of good tutors: subject matter expertise, student engagement, and personalised instruction. The app's content developers use natural-language-processing tools to audit and improve over 100 courses in more than 40 languages. Duolingo also uses gamification, text-to-speech tech, and fine-tuned notification systems to keep learners engaged. Finally, the app's Birdbrain technology gives each learner a personalised lesson.

At Duolingo, humans and AI work together to create a high-quality learning experience

Duolingo, the language-learning app, has been using artificial intelligence (AI) to create personalised educational experiences for its users. Through its AI system, called Brainbird, Duolingo has been able to analyse how users interact with the app and identify areas of strength and weakness. This allows the Duolingo app to adjust the lessons and exercises to make the experience more engaging and efficient, resulting in a more personalised experience for each user.

Moreover, AI helps Duolingo analyse user responses to identify common grammar mistakes and make corrections and suggestions. It also analyses the sounds and patterns of a user's speech to provide targeted feedback on their pronunciation. The auto-suggest feature in Stories freeform writing exercises helps learners write in the language they're learning. All of these features work in tandem to create a more immersive and engaging experience for the user.

I'll go into how Brainbird works later on in this post, but the key takeaway is to understand that Duolingo’s goal is to make learning fun and accessible to everyone. This is how they build brand loyalty and enhance customer engagement using emerging technologies.

AI is at the heart of the Duolingo app

AI is used in even the smallest details, such as the custom voices created for Lily, Zari, Oscar, and all of Duolingo's world characters. This attention to detail not only makes the learning experience more enjoyable but also helps learners to feel more connected to the app and the language they are learning.

Duolingo also uses AI to deliver the Duolingo English Test, aka DET, its high-stakes English Proficiency exam, securely to hundreds of thousands of test takers worldwide. The research team behind the DET has been using AI since its beginning to make the test do everything a traditional in-person, paper-based test can do but in half the time and less than half the cost. Computer-adaptive technology makes the test shorter, automated item generation and scoring make it more affordable, and secure at-home testing makes it more accessible to more people.

However, Duolingo acknowledges the importance of maintaining important security and safety standards, especially for the DET, which has been using GPT-3 since 2021 to make the test more engaging and more effective at assessing proficiency. DET scores are used for international university admissions, so the stakes are high. Therefore, it's important to have clear and transparent guidelines for how to use the latest technology.

Duolingo Brand Strategy: Duolingo offers free language learning with gamification elements and personalised curriculum. It uses crowdsourcing to create and expand courses, and relies on AI, cloud computing and automation to scale operations with a lean team. It has diversified revenue streams with a premium subscription service, an English proficiency test and a new app for children.

Duolingo launches new subscription tier with access to AI tutor powered by GPT-4

In March 2023, Duolingo launched a new subscription tier featuring two AI-powered features called "Roleplay" and "Explain My Answer." These features are powered by OpenAI's GPT-4 and called Duolingo Max, costing $29.99 per month.

The Roleplay feature unlocks an AI chatbot that allows users to practice real-world conversation skills with characters in the app. The chatbot is both responsive and interactive, thanks to GPT-4. Users can practice different scenarios, such as ordering coffee at a café in Paris or discussing future vacation plans with a certain character in the app. After the conversation, users receive AI-powered feedback on the accuracy and complexity of their responses, as well as tips for future conversations.

The scenarios in Roleplay are written by human experts, who ensure that the initial prompt is aligned with the user's course progress. The experts also write the initial message in the chat and guide the AI model through the conversation.

The Explain My Answer feature allows users to learn more about their response in a lesson, whether their answer was correct or incorrect. Users can enter a chat with Duo after certain exercises to get an explanation on why their answer was right or wrong, and ask for examples or further clarification. The feature is designed to help users when they make a mistake and are unsure of the right answer. It can also help in instances where users keep making the same mistake and are not sure why.

These new features are only available for Spanish and French courses for English speakers on iOS. Duolingo plans to roll out the features to more courses and platforms soon.

Duolingo Max comes with unlimited hearts, no ads, and personalised review through the app's Practice Hub. The company constantly reviews AI-generated explanations in Roleplay and Explain My Answer to ensure factual accuracy and the right tone.

"We know that technology is never perfect," the company said in a blog post. "Part of the reason we're so excited to use GPT-4 for these features is that it's the most accurate (and fastest) version of the technology available. We've spent months collaborating closely with OpenAI to test and train this technology, and will continue doing so until the mistakes are nearly nonexistent."

Duolingo's key to success is in Brainbird, it's AI system

When material is too difficult, students tend to get frustrated and quit. Conversely, material that is too easy may keep them engaged, but it doesn't challenge them enough. To address this, Duolingo uses AI to keep its learners engaged in a zone where they are still learning at the edge of their abilities.

Duolingo's early machine-learning work tackled simple problems such as determining how often to return to a vocabulary word or concept. As the company grew, it doubled down on building personalised systems. Its first version of Birdbrain used logistic regression to predict how likely a learner is to get an exercise correct, based on the exercise's difficulty and the learner's current proficiency. Birdbrain V2, the improved version, updates a richer model of what each learner knows in real time using a recurrent neural-network model, allowing for more personalisation in the lessons that Duolingo prepares for that individual.

Birdbrain V2 consistently improved engagement and learning measures, and in May 2022, Duolingo switched entirely to the new and improved system. Scaling up Duolingo's AI systems required inventive engineering due to the sheer scale of data that it needed to process. One issue with the first version of Birdbrain was fitting the model into memory. Duolingo's solution was to break up the model into smaller pieces that represented different parts of the model, making it more manageable.

Another issue with the first version of Birdbrain was that it updated its models only once every 24 hours, which was addressed in Birdbrain V2 by processing all exercises in real-time. Birdbrain V2 also uses a recurrent neural-network model to create richer representations of a learner's knowledge state, allowing for more personalisation in the lessons that Duolingo prepares.

Duolingo hopes to create adaptive systems that respond to learners based not only on what they know but also on the teaching approaches that work best for them, emulating some of the qualities of great teachers.

Setting the standards for the ethical use of AI

Duolingo has tested the new technology with its teams and a small group of users for months and was impressed by the results. Duolingo is also making a deliberate effort to develop standards for practicing responsible AI and to lead the industry in formalising those standards. The educator’s responsible AI standards are best practices for ensuring accountability, transparency, fairness, privacy, and security in testing.

While generative AI will continue to evolve in ways we can't yet imagine, Duolingo has a lot of experience working with this powerful technology. It will continue to use its incredible capabilities to improve the lives of learners all over the world as part of its mission to make high-quality education available to everyone on the planet. From high-stakes English proficiency testing to language, math, and literacy lessons, Duolingo is at the forefront of AI in personalised education and learning.

Duolingo’s Brand Strategy

Duolingo's business strategy is to provide free and accessible language learning to millions of users around the world, while generating revenue from various sources such as subscriptions, ads, tests and a new app.

  • Duolingo uses gamification elements in its product, such as levels, rewards, streaks and leaderboards, to make learning fun and engaging. It also uses data and artificial intelligence to personalise the learning experience and optimise the curriculum for each user.
  • Duolingo leverages crowdsourcing to create and expand its courses in different languages. It has a platform called Incubators, where volunteers can contribute their linguistic expertise and cultural knowledge to design new courses or improve existing ones.
  • Duolingo has a low cost per user, as it relies on AI, cloud computing and automation to scale its operations. It also has a lean team of about 400 employees, most of whom are engineers and designers.
  • Duolingo has diversified its revenue streams over time, as it realised that ads alone were not enough to sustain its growth. It launched a premium subscription service called Duolingo Plus, which offers ad-free and offline access, as well as additional features like progress quizzes and unlimited hearts. It also offers an English proficiency test called Duolingo English Test, which is accepted by over 3,000 institutions worldwide. It also launched a new app called Duolingo ABC, which teaches children how to read.

Further Reading

  • How Duolingo became an edtech leader. Source
  • How does Duolingo work & make money: Business Model & Strategy. Source
  • Lot to Learn from Duolingo Marketing Strategy?. Source
  • What B2B companies can learn from Duolingo’s growth strategy. Source
  • 3 Brilliant Duolingo Social Media Strategies | by Shawn Lori Cannon .... Source
  • How Duolingo Built a $700 Million Company. - BusinessWritingBlog. Source
  • How Duolingo uses AI in every part of its app. Source
  • The Amazing Ways Duolingo Is Using Artificial Intelligence To Deliver Free Language Learning. Source

Examples of other firms using GPT for better customer engagement

  • Shopify has integrated an online shopping assistant that allows customers to have a conversation with the platform.
  • Instacart has implemented an AI chatbot feature called “Ask Instacart”.
  • The Coca-Cola Company has signed a deal with OpenAI and Bain Consulting to implement ChatGPT and DALL-E into its marketing and global operations.
  • Snapple, the Dr Pepper iced tea brand, is engaging with their customers by giving them access to ChatGPT to create their own interesting facts.
  • Quizlet, the online learning platform, has integrated ChatGPT to ast as an online tutor.

Quizlet, the digital education platform using AI

Quizlet is an online learning platform with 60 million monthly users who have integrated ChatGPT into the online learning experience. Students can ask questions of ChatGPT to help develop their understanding, just as they would ask the teacher in a classroom.

Quizlet describes “Q-Chat” as the first fully adaptive, AI-powered tutor experience built on OpenAI’s ChatGPT API. It’s designed to make studying fun and effective and can help students learn by quizzing them on their set material. Q-Chat leverages Quizlet's massive educational content library, which includes billions of questions and definitions, in conjunction with AI models from OpenAI to provide a virtual tutor experience to students. Q-chat automatically quizzes students and helps deepen their knowledge of whatever concepts they are learning in a conversational and engaging way.

Quizlet has long invested in AI to make studying more engaging and effective for students. Since 2020, the company has collaborated with OpenAI, leveraging GPT-3 across multiple use cases, including vocabulary learning and practice tests. AI and machine learning also underpin Learn Mode, which launched in 2017 and helps students learn their material faster through personalized and adaptive study experiences.

Quizlet's student-first strategy for integrating AI into its platform garnered national recognition in 2022, with Fast Company naming Smart Grading as one of the Next Big Things in social good and education for its ability to "better assess a student's written response for signs of conceptual understanding, rather than solely rewarding rote memorization."

"Quizlet has long recognized the potential of AI to enhance studying and learning by personalizing the student experience," said Lex Bayer, Chief Executive Officer, Quizlet. "As an early adopter of this technology, we know that when used effectively it can help students deepen their knowledge and learn more efficiently. We look forward to continuing our collaboration with OpenAI and providing our students with more ways to practice and master whatever they're learning."

Wiser! Reading


Brand Strategy Collection

"Brand Strategies in Emerging Tech" is a unique collection of over 250 consumer brands and their strategies in the emerging technologies of AI, VR, Web3 and other emerging and game-changing new technologies.

Over the past year, I have tracked, traced, analysed and assessed over 250 consumer brands and their projects, initiatives and use-cases to build increased customer engagement, loyalty and win new markets...all using emerging technologies.

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