As the world’s #1 language learning app, Duolingo knows entertainment content drives interest in language learning and vice versa. From K-pop music to television shows like Squid Game, our data shows a direct correlation between user growth and what’s happening in the cultural zeitgeist.

So when HBO Max announced a new prequel to the Game of Thrones series named House of the Dragon, Duolingo saw an opportunity to join the conversation and drive brand awareness. How? By speaking the show’s language.

For the new Game of Thrones prequel House of the Dragon, Duolingo partnered with HBO Max to create High Valyrian lessons that teach fans the fictional language from the show.

We launched the lessons ahead of the season premiere with multiple buzzworthy activations including cryptic billboards in Times Square and Comic-Con, an in-app challenge with a life-size Valyrian Steel sword as the prize, and viral social content featuring Duo the Owl on the iron throne at HBO Max’s Comic-Con event.

By tapping into the insight that nearly half of those who learn a fictional language go on to learn a real one next, we were able to focus on promoting a magical made-up language that would receive global attention while knowing that fans would eventually sign up for our other real languages down the line.

HBO Max was looking to engage fans after the original Game of Thrones series had ended years before. Knowing millennials, who make up Duolingo’s target audience, are obsessed with Game of Thrones and the new House of the Dragon series would feature its fictional language, we were confident an idea based on High Valyrian would speak to our audience too. We also knew nearly half of those who sign up for a fictional language go on to learn another like Spanish or French next.

So we turned this insight into a cultural phenomenon by partnering with HBO Max to promote High Valyrian lessons with the key message of "Learn High Valyrian on Duolingo." We focused on the most relevant entertainment media outlets (Variety, Nerdist, Rolling Stone) and launched our lessons during the week of Comic-Con to maximize impact in the press.

We developed our High Valyrian lessons with the inventor of the language himself, David Peterson. The course and corresponding social content taught fans real phrases from episodes such as “Umbās” and “Lykirī”, which also doubled as dragon commands in HBO Max’s new augmented reality app.

For launch, Duo the Owl shared an iconic illustration of himself sitting on the iron throne. Then, he showed up in real-life at HBO Max’s Comic-Con activation to claim the iron throne and encourage learners to do their lessons as seen in our viral TikTok.

To keep the dialogue going all season long, Duo the Owl exchanged weekly tweets in High Valyrian with HBO Max after every episode. And to add another plot twist, he hosted a challenge where learners battled it out on the Duolingo leaderboard for the #1 spot. The prize? A life-size Valyrian Steel sword engraved with a secret phrase.

From Fast Company in the US and the Independent in the UK to El Universal in Mexico, High Valyrian Lessons became the #1 most talked about campaign for Duolingo ever and helped drive fans to HBO Max’s most watched premiere in history. The unexpected partnership generated more than 150 press mentions and 700M earned media impressions around the world with a single TikTok video receiving 10.8M views alone. All of this attention led to a massive increase in new inbound partnership opportunities. The campaign also created a lasting cultural impact with one learner even deciding to hold her entire wedding in High Valyrian. So far over 300,000 fans have started learning High Valyrian, but most importantly 43% of them will go on to learn another language like Spanish or French next.