What Duolingo’s TikTok Teaches Brands.

The Duolingo TikTok account is usually discussed as a mascot with a sense of humour, but Duolingo’s own shareholder letters describe something more useful to brands: a growth channel built on organic social, with no sales pitch in the posts.

In its letter for the second quarter of 2023, published on 8 August 2023, Duolingo told investors it had become one of the most followed brands on TikTok globally. It credited what it calls social-first marketing. And it said plainly that it does not sell directly in its campaigns: readers, it wrote, have never seen a “try Duolingo” button on any of its social posts.

That is a public company putting its social approach in front of shareholders, in a regulatory filing. It is the clearest public case we know of that entertainment-first social can be a growth channel rather than a brand cost.

What Duolingo told its shareholders

The Q2 2023 letter is signed by Luis von Ahn, Duolingo’s chief executive and co-founder. He used it to focus on the company’s marketing, “why it works, and how it helps with our user growth”.

The core claims are short. Word of mouth, the letter says, “has been our most powerful growth lever since the beginning”. Duolingo spends “relatively little on paid user acquisition”, meaning advertising bought to win new users, and “the vast majority of our users have been acquired organically”.

The earlier letter for the fourth quarter of 2022, dated 28 February 2023, put a figure on it. It said “90% of our user growth has been organic”. Duolingo explained that it did not make money from the app for years after launch, so it did not want to spend to acquire users. It found that the most cost-efficient growth came from making the product fun enough that people told friends and family.

What social-first marketing means at Duolingo

Duolingo defines the strategy in its own words. It inserts the brand “into pop culture events and social media moments in order to expose it to new audiences and drive word-of-mouth growth”. It calls this social-first marketing.

In practice, the letter describes three habits:

• Content made to delight and engage audiences, so that they share it on social media.
• Tapping into trending topics and major pop culture moments.
• No direct selling in the campaigns themselves.

The letter adds that this approach is “relatively low cost”. It says it has generated “outsized returns in terms of social media impressions, press coverage, and, ultimately, new users to Duolingo”. Impressions here means the number of times its content was shown.

The missing call to action

The detail most brands will find hardest to copy is the absence of a call to action. A call to action is the line or button that tells a viewer what to do next: download, sign up, shop now.

In our experience, many brand social teams are judged on that click. Duolingo’s letter describes posts with no “try Duolingo” button at all. The content is the product’s advertisement only in the sense that people remember the brand and talk about it.

Our view is that this is the real lesson, not the mascot. A post that asks for nothing can be watched, shared and enjoyed without the viewer feeling sold to. The same instinct sits behind our argument for organic growth over paid ads: attention you earn compounds in a way that attention you rent does not.

Fans did a lot of the work

The letter describes learners as brand ambassadors. Fans share their experiences, engage with Duolingo’s posts and create their own content about the brand.

It makes one striking claim about scale. Duolingo says it has “seen user-created content on TikTok and YouTube outpace impressions of our own posts”. In plain terms, videos made by fans were seen more often than the videos Duolingo made itself.

The letter also shows how that fan content fed back into the business. It says Duo, its mascot, is loved globally, but that Lily, a purple-haired emo teenager among its characters, is adored by learners in China. Fan content about Lily spread across Chinese social media. Duolingo responded by making Lily plushies and stickers for its new merchandise store.

The numbers behind the claim

The same Q2 2023 letter gives the figures Duolingo chose to put next to its social strategy:

• Social media impressions grew 150% year over year, meaning two and a half times as many as a year earlier.
• Daily active users, the average number of people using Duolingo each day over the quarter, rose 62% to 21.4 million compared with the same quarter a year earlier.
• Sales and marketing costs fell from 17% to 14% of revenue over the same year.

We would read these with care. The letter does not say social posts caused the user growth on their own, and a company’s product, pricing and word of mouth all move together. What the letter does say is that social-first marketing drove brand awareness and word-of-mouth growth, and that its marketing had become “an increasingly efficient complement to our organic user growth”.

Big moments, built to be shared

One example the letter gives is the annual April Fools prank, which it says has grown in scale every year. In 2023 Duolingo partnered with NBC’s Peacock to create Love Language, a made-up dating reality show in which the contestants do not speak each other’s language.

It also notes industry recognition. Ad Age named Duolingo one of its Hottest Brands in 2022, and in June 2023 the company won its first Gold Lion at Cannes for its High Valyrian Lessons campaign.

These are big, planned moments. They sit on top of a steady flow of everyday posts, which is where most brands can actually compete.

What most brands get wrong when they copy it

Most attempts to copy Duolingo copy the surface: an unhinged mascot, a meme format, a reply to a celebrity. In our reading, the letter describes a set of decisions underneath that:

1. It reports the returns from social as impressions, press coverage and new users, not as clicks from each post.
2. It kept selling out of the content.
3. It built on a product people already talked about. The letter credits a product that is “free, fun, and effective” for its word of mouth.
4. It listened to what fans made, then acted on it, as with Lily.

Our view is that without the first two, the tone alone reads as a brand trying too hard. Fixing that is a workflow and sign-off problem before it is a creative one, which is the work behind our social media management.

Where the model has limits

Duolingo had advantages most brands do not. The letter describes a product that is “free, fun, and effective”, and one learners already recommend to friends and family. A business with a long buying cycle or a product nobody discusses at dinner will not get the same word of mouth from the same posts. Humour is harder than it looks too, as we set out in why brand humour falls flat with Gen Z.

The letters also describe Duolingo’s position in 2022 and 2023. They are a record of what the company told investors at that time, not a description of how its social works today.

The lesson still travels. Decide what social is for, measure it on that, and stop asking every post to close a sale.

How NBK thinks about entertainment-first social

We think of this as a system question, not a creative one. Removing the call to action is easy. Getting a sign-off chain to accept a post that sells nothing is hard, and that is where most brands stall.

The work is in the operating rhythm: a clear purpose for the channel, measures that match it, a fast route from a trending moment to a published post, and someone whose job is to read what fans make. That is the system we build, drawing on team experience across publishers including UNILAD and LADbible Group.

Next step

If every post still has to justify itself in clicks, the constraint is probably the brief, not the content. If your team is posting regularly but still feels stuck, NBK can help find the constraint in the system.