Duolingo — Language Lessons

# Build brief — an original mobile app in the taste of Duolingo

> Reference: https://apps.apple.com/us/app/duolingo-language-lessons/id570060128 · UIDiscovery: https://uidiscovery.com/sites/ios-duolingo · captured 2026-09-23

## 1. Goal
Build an original mobile app for **[the user's brand]** that feels as considered as Duolingo — same structure, rhythm and polish, entirely new identity and content. Stack: SwiftUI, React Native/Expo, or a mobile-first web app.

## 2. Originality rules
- Build an ORIGINAL design for the user's own brand in the same *taste* as Duolingo: structure, rhythm, hierarchy, palette mood and type pairing.
- Never reuse Duolingo's logo, name, product imagery, illustrations, icons, screenshots or copy. Write new copy for the user's product.
- If the user hasn't said what their product is, ask first (or use clearly marked placeholders like [Brand], [Product], [Audience]).
- Reference screenshots are for looking at, not for embedding or tracing.

## 3. The taste, in short
- Duolingo is a Education iOS app; 567 screens captured plus 1 recorded journey (Onboarding).
- Screens are captured from the app itself.
- Palette and fonts are NOT measured for iOS references — sample them from the screenshots.

## 4. Screens

Every screen needs: Status bar + navigation; Primary content; Primary action / tab bar; Empty and loading states.

1. [duolingo](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-01-60ff278e525a.webp) (title machine-read, unverified)
2. [duolingo](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-02-60ff278e525a.webp) (title machine-read, unverified)
3. [Hi there! I'm Duo!](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-03-60ff278e525a.webp) (title machine-read, unverified)
4. [Set expectations before asking questions](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-04-60ff278e525a.webp) — The introduction says there are seven quick questions before the first lesson. A single Continue button moves forward.
5. [What would you like](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-05-60ff278e525a.webp) (title machine-read, unverified)
6. [Choose the subject first](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-06-60ff278e525a.webp) — French is selected in a language list. The selection has a blue background and the Continue action is enabled.
7. [What would you like](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-07-60ff278e525a.webp) (title machine-read, unverified)
8. [Adjust the starting level](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-08-60ff278e525a.webp) — The learner chooses how much French they know from a set of progressively stronger statements.
9. [Why are you](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-09-60ff278e525a.webp) (title machine-read, unverified)
10. [Allow more than one motivation](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-10-60ff278e525a.webp) — Three reasons for learning are checked at once. The list uses separate checkbox-like indicators.
11. [What's your daily](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-11-60ff278e525a.webp) (title machine-read, unverified)
12. [Make the commitment concrete](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-12-60ff278e525a.webp) — The daily learning goal is expressed in minutes per day, with ten minutes selected.
…and 555 more at https://uidiscovery.com/sites/ios-duolingo.

## 5. Design system
- Colour: not measured. The listing hints at `#f8f8f8` (probably from the icon) — a hint only. Sample background, text, accent and surface from the screenshots, then check contrast.
- Type: SF Pro natively (Dynamic Type: Large Title 34, Title 22–28, Body 17, Footnote 13); on the web use Inter or system-ui at the same sizes.
- Layout: 16–20pt side margins, 44pt minimum tap targets, safe areas, tab bar or navigation stack as seen in the screens; cards with 12–20pt radii are typical — confirm in the screenshots.

## 6. Imagery plan

iOS references show the product UI itself: build screens in code. What you still need to source is the content imagery inside them (covers, thumbnails, onboarding art).

### Slot 1 · All 12 screens → product UI
- iOS screen: the visual is the app UI itself; any photos/illustrations inside it are content. Count: one consistent treatment across these sections. Aspect: 9:16 (portrait, phone). Look first: [ref 1](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-01-60ff278e525a.webp) [ref 2](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-02-60ff278e525a.webp) [ref 3](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-03-60ff278e525a.webp) [ref 4](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-04-60ff278e525a.webp)
- Build every screen in code. Don't reproduce App Store marketing frames or the app's own artwork.

### Slot 2 · In-app content imagery (covers, thumbnails, onboarding art) → illustration (uncertain)
- Education apps often use illustration for content — not measured; check the screenshots. Count: one consistent style across all content. Aspect: 1:1 thumbnails, 4:5 covers. Look first: [ref 1](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-01-60ff278e525a.webp) [ref 2](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-02-60ff278e525a.webp) [ref 3](https://uidiscovery.com/media/captures/ios-duolingo/flow-onboarding-jan-2026/step-03-60ff278e525a.webp)
- **Stock** — “education flat illustration”: [Unsplash](https://unsplash.com/s/photos/education-flat-illustration?orientation=portrait) · [Pexels](https://www.pexels.com/search/education%20flat%20illustration/?orientation=portrait) · [Pixabay](https://pixabay.com/images/search/education%20flat%20illustration/?orientation=vertical)
- **Generate** — `Flat vector illustration: students studying together, friendly simplified shapes, limited palette of colours sampled from the reference screenshots (the listing hints at #f8f8f8) plus one soft neutral, plenty of empty background, consistent line weight, neutral, desaturated mood. Aspect ratio 4:5. No text, no letters, no logos, no watermarks, no brand marks or trademarked products, no recognisable real people.`
- Uncertain: this could equally be photography, a product shot or icon art — open the reference screenshots and match what you see.

- **Licences:** Unsplash and Pexels images are free for commercial use under their own licences; Pixabay under the Pixabay Content License. Check each image's page before use, credit the photographer when asked (good practice anyway), and skip images showing logos, trademarks, branded products or identifiable people without a release.
- **AI generation:** the prompts work with any image model (GPT Image, Imagen, Flux, Midjourney, Firefly, SDXL…) — check its commercial-use terms. Never put the reference brand's name or “in the style of <brand>” in a prompt.
- **Never** download, trace or re-host the reference's own images, illustrations, product shots or logos.

## 7. Build steps
1. Confirm brand, product, audience and the primary action with the user.
2. Pick the stack and define colour/type tokens sampled from the screenshots.
3. Build the navigation shell first, then each screen, with each reference screenshot open.
4. Write original copy for every slot — match length and tone, never the words.
5. Source every image via the imagery plan (stock or generated); compress it and record credits.
6. Run the checklist at 390 / 768 / 1440px and fix what fails.

## 8. Acceptance checklist
- [ ] Responsive at 390px, 768px and 1440px — no horizontal scroll, tap targets ≥ 44px on mobile.
- [ ] Colour contrast WCAG AA: 4.5:1 body text, 3:1 large text and UI; visible focus states; full keyboard navigation.
- [ ] Semantic HTML: one <h1>, ordered headings, landmarks (header/nav/main/footer), labelled form fields, alt text on meaningful images.
- [ ] Performance: modern image formats with width/height set, lazy-load below the fold, ≤ 2 font families with font-display: swap, LCP < 2.5s.
- [ ] prefers-reduced-motion respected; animations under ~300ms and never blocking content.
- [ ] Originality: no copied logos, images, illustrations or copy from the reference; every image licensed or generated; credits recorded.

## 9. If you use Next.js + Tailwind
Mobile web: App Router + Tailwind, `viewport-fit=cover` with safe-area insets, a fixed bottom tab bar, components designed at 390px first.

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More: tokens https://uidiscovery.com/api/v1/sites/ios-duolingo/tokens · kit https://uidiscovery.com/api/v1/sites/ios-duolingo/kit · MCP `get_design_brief({ slug: "ios-duolingo" })`, `get_image_plan({ slug: "ios-duolingo" })`. Cite the reference as https://uidiscovery.com/sites/ios-duolingo.