Yomu (読む)

A Japanese vocabulary learning app for iOS, combining a powerful JMdict-powered dictionary with a WaniKani-style spaced repetition system.

読む (yomu) means “to read” in Japanese

Highlights

JMdict dictionary with 200,000+ entries and smart verb deinflection
10-stage SRS inspired by WaniKani for long-term retention
Native iOS experience using SwiftUI components and Liquid Glass effects
Reading session timer with Live Activities support in Dynamic Island
Fully offline - all data stored locally with backup/restore

Overview

Yomu is a personal Japanese vocabulary learning tool built for iOS. It lets you search a comprehensive Japanese-English dictionary, add words to your flashcard deck, and review them using a proven spaced repetition algorithm.

The app prioritizes a native iOS experience, using SwiftUI components via Expo’s @expo/ui and the new Liquid Glass visual effects from expo-glass-effect. It requires iOS 18+ and a development build (not compatible with Expo Go).

Why Yomu?

Smart search: Type in Japanese (kanji, hiragana, katakana), romaji, or English
Verb deinflection: Recognizes conjugated forms (食べている → 食べる) with 400+ rules
WaniKani SRS: Battle-tested algorithm with Apprentice → Guru → Master → Enlightened → Burned stages
Context-rich cards: Add example sentences, translations (via DeepL), and photos to your flashcards

Features

Dictionary & Search

Search the complete JMdict database with support for:

Japanese input (kanji, hiragana, katakana)
Romaji (automatically converted to hiragana)
English definitions
Conjugated verb forms via deinflection (e.g., 食べたくなかった → 食べる)

Results are ranked by relevance and word commonality.

Flashcard Deck & SRS

A 10-stage spaced repetition system modeled after WaniKani:

Stage	Name	Interval
0	New	Immediate
1-4	Apprentice	4h → 8h → 1d → 2d
5-6	Guru	1 week → 2 weeks
7	Master	1 month
8	Enlightened	4 months
9	Burned	Complete

Incorrect answers apply a penalty that scales with stage level, ensuring difficult cards get more practice.

Card Enrichment

Add custom example sentences
Automatic translation via DeepL API (optional)
Attach photos for context using the camera

Reading Sessions

A stopwatch timer to track your study time while reading external materials:

Live Activities support - see elapsed time in Dynamic Island
Tracks cards added during each session
Session history with statistics

Statistics Dashboard

Total cards, active cards, burned cards
Current and best streak tracking
Success rates (all-time, 7-day, 30-day)
Stage distribution visualization
GitHub-style activity heatmap
30-day review forecast chart

Backup & Restore

Export all your data to a ZIP file including:

Cards with full review history
Reading sessions and daily stats
Card images
Settings (optionally with API key)

Technical Highlights

Architecture

React Native with Expo SDK 54
SQLite database via expo-sqlite for all data
Zustand for state management (one store per feature domain)
NativeWind (Tailwind CSS) for styling

Native iOS UI

SwiftUI components via @expo/ui/swift-ui (Button, TextField, Switch, Picker, etc.)
Liquid Glass effects via expo-glass-effect
Native tab bar with expo-router/unstable-native-tabs
SF Symbols for icons
iOS system colors with automatic dark/light mode

SRS Algorithm

The spaced repetition algorithm follows WaniKani’s proven formula:

Correct answer: Advance one stage
Incorrect answer: Drop back based on current stage (higher stages = bigger penalty)
Cards answered incorrectly stay in the current session for immediate re-review

Getting Started

Requirements

iOS 18+ (uses Liquid Glass and other iOS 18 features)
Development build required (not compatible with Expo Go)
Node.js and npm
Xcode with iOS 18+ SDK

Installation

Clone the repository:

git clone https://github.com/YannickHerrero/yomu.git
cd yomu

Install dependencies:
```
npm install
```

Create a development build:

npx expo run:ios

Or using EAS Build:

eas build --profile development --platform ios

Start the development server:
```
npm start
```

Building the Dictionary

The app requires a pre-built dictionary database. To build it from JMdict:

Download JMdict_english.zip (without example sentences) from yomidevs/jmdict-yomitan

Extract the contents to assets/JMdict_english/:

unzip JMdict_english.zip -d assets/JMdict_english

Run the build script:
```
npm run build:dictionary
```

This converts JMdict data to SQLite format with full-text search indexing.

Project Structure

app/                    # Expo Router screens
├── (tabs)/
│   ├── dictionary/     # Search & add cards
│   ├── review/         # Deck, sessions, burned cards
│   ├── session/        # Reading timer
│   ├── settings/       # Preferences, backup
│   └── stats/          # Statistics dashboard
components/             # Reusable UI components
database/               # SQLite queries by domain
stores/                 # Zustand state management
utils/                  # SRS calculations, deinflection, etc.
constants/              # SRS stages, theme values

Contributing

Contributions are welcome! Feel free to open issues for bugs or feature requests.

If you’d like to contribute code:

Fork the repository
Create a feature branch
Make your changes
Open a pull request

License

MIT License - see LICENSE for details.