The archive · Product Ideas · Product decision · 2024–2026
Duolingo's Video Call turns language practice into a call with AI character Lily
Instead of one more drill, Duolingo lets Max subscribers call its sarcastic character Lily for a free-flowing AI conversation that adapts to their level.
Duolingo
What it had to solve
Learners feared speaking: the app's drills tested grammar, but real conversation needed a partner who would not judge. Duolingo Max, the subscription tier, wanted a reason to exist beyond more drills.
How it works
At Duocon 2024, Duolingo announced Video Call, a feature that lets Duolingo Max subscribers ring up Lily, one of the app's most popular characters, and hold a spontaneous conversation in the language they are learning. No lesson plan and no penalty for mistakes — just a one-to-three-minute chat.
The design was deliberate about psychology: Lily adapts to the learner's level, does not correct grammar mid-conversation, and can be asked to repeat or slow down. Product manager Zan Gilani told PCMag that constant correction activates the monitoring part of the brain and takes away from active communication.
Under the hood, Lily is a fine-tuned OpenAI model wrapped in Duolingo's own product structure — she pauses while 'thinking', remembers what you said in earlier calls, and shows rough mouth shapes as she speaks. Launch languages were English, Spanish and French, widening to German, Italian, Portuguese, Japanese and Korean.
The move turned the app's most sarcastic character into a judgment-free practice partner and made live AI conversation the centerpiece of the Max subscription, signaling where Duolingo planned to push its AI investment next.
Why it lands
- Speaking is a muscle, but learners had no low-stakes partner — an AI character removed the judgment that drills cannot remove.
- Using an existing beloved character gave the feature personality and attachment instead of a generic chatbot.
- Not correcting every mistake kept the conversation flowing, training real communication rather than grammar recall.
- Because the AI remembered past calls, the practice felt continuous, like a friend you keep catching up with.
What it did
Every Max subscriber gained an on-demand, judgment-free speaking partner, and the feature became the centerpiece of Duolingo's AI story at Duocon 2024. It launched in English, Spanish and French, widening to German, Italian, Portuguese, Japanese and Korean.
What you can take
The best use of AI in a learning product is not a smarter quiz but a social simulation — a low-stakes partner removes the fear that drills cannot touch.
Since then
Video Call became a flagship Duolingo Max feature: the company widened it from three launch languages to include German, Italian, Portuguese, Japanese and Korean, and followed with Adventures, an AI-driven exploration mode announced at the same Duocon. Duolingo kept publishing about the AI behind the calls through 2025, and its investor materials highlighted the feature as proof the company could ship AI experiences at scale. The design — a character who never embarrasses you — became a template for the industry's AI conversation features.
Sources
- Video Call lets you have real life conversations with Lily
- Duolingo Launches $249 E-Piano, Updates App With AI Chats, New Worlds
- Duolingo Introduces AI-Powered Innovations at Duocon 2024
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