Desktop and mobile app
Vocabularify
Learn a language by doing nothing: words drift past while you work.
Words drift past while you work, then short sentences built only from the words you have already seen. Seven languages in 42 pairs from A1 to C1, with the lessons and sentences generated from one word bank by a compiler I wrote for it. Desktop and mobile share the data; the iOS build is in TestFlight.
What I did
Product, the sentence compiler, both apps and the landing page.
- Designed the rule that makes the app honest: a sentence may only use words the learner has already been taught.
- Wrote a sentence compiler with a 3-line notation per sentence, so a course of 2,000+ sentences is cheap to write and lint.
- Built 42 language pairs from one bank of about 6,000 concepts per language, A1 to C1, with a grammar syllabus per level.
- Wrote the desktop app in Electron and the mobile app in React Native, sharing the course data.
- Rebuilt the landing page with real screenshots taken from the running apps.
The decisions, and why
- Only taught words, no exceptions
- A sentence with one unknown word teaches nothing and costs trust. The compiler refuses to build one.
- Generate courses, do not hand-write them
- 42 pairs by 5 levels is 210 courses. Hand-written, that is a year of typing; generated from one bank, a new source language costs one diff.
- Passive first
- The learner is working. The app shows a word every few minutes and asks nothing until the lesson is done.
Built with
- Electron
- React Native
- Expo
- TypeScript
- Python
The numbers, and where they come from
- Languages
- 7
- 42 source and target pairs
- Lessons
- 5,400+
- across the 7 courses, 16 Sep 2026
- Sentences
- 16,600+
- built from taught words only
- Levels
- A1 to C1
- every pair
Performance scores move a few points between runs on any site, including these. Paste the address into PageSpeed Insights and run it yourself.
More from the portfolio
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