A product concept exploring what happens when language practice stops resetting every time you close the app. I researched it, scoped it, and built a working prototype the way I'd actually bring it into a roadmap review.
I'm a longtime Duolingo user, and the thing that's never quite worked for me is the gap between finishing a lesson and actually being able to say something out loud in Spanish. I'd pass every exercise in a unit and still freeze the one time I needed to order a coffee for real.
So I went looking for whether Duolingo had already noticed this. They had. Adventures, shipped in 2024, drops you into a Duolingo character's shoes to complete one scenario per course unit. Speaking Adventures, rolling out through 2026, pushes the same idea into voice. Both are genuinely good. Both are also one-and-done: you finish the scenario, the app moves on, and nothing about that visit carries forward to the next time you open it.
That shows up in how people actually talk about the app, real quotes a few sections down. Picking the right answer out of a list is one skill; generating language on your own, under pressure, is a different one, and Duolingo trains the first far more than the second. The other recurring complaint is simpler: the same handful of scenarios, and nothing changes if you play one again.
Both point at the same thing: nothing about Adventures persists. So I stopped asking what a fun new scenario would look like, and asked a smaller question instead.
There's a real psychological reason this matters, not just a UX one. Foreign Language Speaking Anxiety research points to a specific fix: repeated, contextualized practice that feels like spontaneous real use. That's what actually lowers the fear of speaking, not more vocabulary.
I went looking for the two complaints directly, in app store reviews and review aggregators. The same two patterns showed up in every one I checked.
Duolingo City is a persistent world, living in its own tab, where the locations you've practiced in stay open, and the people in them remember you. Go to the café once. Come back next week, and the barista's first line isn't generic. It references how long it's been since you last came by, pitched to how you've actually been performing in conversation, not just which grammar unit you checked off.
It's not a new character system, a new economy, or a new social feature layered on top of Duolingo. It's the smallest version of "a city that remembers you" that doesn't require inventing any of those three things.
A working build of the loop this whole concept is built around, in the same visual language as today's Duolingo. Click through it, the notes on the right update with what each screen is actually doing.
Skip ahead to the live prototype →The storyboard above is a walkthrough of the idea. What's below is the same three screens, live, not staged, starting from the city map rather than mid-conversation.
Tap a location, then talk through a few turns, the notes above track which screen you're on.
This ended up being the most important design decision in the whole concept.
On purpose: it's a structured profile per person, per location, that selects from a small bank of pre-written dialogue variants. Nothing is generating a fresh conversation from scratch.
Each location's dialogue is written as a handful of variants, chosen by simple rules: first visit or returning, short gap or long gap, strong or shaky recent performance. It's the same authoring model Duolingo already uses for branching exercises, it scales with writing time, not inference cost, and every line gets reviewed before it ships.
A real city needs more than a café. My first pass at this had six locations active on day one, café, metro, market, hotel, pharmacy, park, because that's what "explorable city" sounds like it should mean. The actual v1 is smaller: Duolingo City as its own tab, with the avatar walking into each scene, a location memory profile per user, per location, and dialogue variants for first-visit, returning-soon, and returning-after-a-gap, adjusted for recent performance. A results screen shows a confidence score alongside something more honest than accuracy: how many responses someone actually produced themselves, without a hint.
Every roadmap slide says "more locations." The harder question is what happens at the café specifically, once a learner has been there enough times that the v1 variant bank runs out of new things to say.