devanagari — alphabet trainers

Personal web app for learning an alphabet by spaced repetition. One codebase serves three courses, each installable as its own app:

• index.html — devanagari: the Devanagari script as used for Nepali, with Latin readings: characters, consonant-vowel combinations, compound characters, daily words, digits and practical Kathmandu phrases by topic.

• russian.html — russian: the Cyrillic alphabet with Devanagari readings, for Nepali speakers; both cases on every card, a group of short words, and everyday phrases by topic. Every card has a pronunciation clip.

• hebrew.html — hebrew: the Hebrew alphabet with Latin readings, final forms as their own group, right-to-left cards, plus a group of short words.

• Static, no build step.

• Install on iPhone: open the course page in Safari, Share, Add to Home Screen. Each course installs as a separate icon; the flags at the top of every course page switch to the other two.

• Works offline after the first visit; progress is stored in the browser per course. A saved progress file names its course and loads only into that one.

A course is a <name>.json character file, an optional <name>-words.json daily-word file, a manifest, and an entry in js/courses.js.

Pronunciation clips are pre-generated mp3 files, one directory per course (audio/devanagari/, audio/russian/), each with a manifest.json listing the clips on disk. A course opts in with an audio: {lang, dir} block in js/courses.js; within its data file, groups flagged "audio": true get a clip per character, speaking the tts field when present and the glyph otherwise. Devanagari voices its phrase groups; Russian voices letters (by name), words and phrases.

Development

python -m http.server 8000    # then open http://localhost:8000
node --test                   # scheduler, course and data tests
node tools/generate-audio.mjs [course] # regenerate that course's clips, default devanagari (needs .venv with gTTS; see tool header)
node tools/generate-icons.mjs # regenerate app icons after a version bump (needs ImageMagick)

Each version gets its own icon background color (derived from APP_VERSION in js/app.js), so parallel installs on the iPhone home screen are easy to tell apart; the Russian and Hebrew icons take the same hue shifted by a third of the wheel and show one letter of their alphabet. Version bump checklist: APP_VERSION in js/app.js, CACHE_VERSION in sw.js, then regenerate the icons.