A speech practice app for iOS and Android, built with Expo.

Read a passage out loud. Clarity listens, scores how you spoke, and tracks your progress over time.

What it does

• Practice — read from a library of passages (stories, news, poetry, tongue twisters), run short drills, or speak freestyle on a random topic. You can also add your own passages.
• Live feedback — a teleprompter follows your voice while you read, with a live word count, waveform, and pace readout.
• Scoring — each session gets one speaking score out of 100, plus five skills: Articulation, Flow, Pacing, Fillers, and Expression.
• AI coaching — a short written note after each session that points at the most useful thing to work on next.
• Analytics — score trend by week, month, or all time, along with practice time, session count, streak, and the words you keep stumbling on.

All history is stored on the device. There is no account and no server database.

Stack

• Expo SDK 57, React Native 0.86, Expo Router (file-based routes)
• expo-speech-recognition for on-device transcription
• Azure Speech pronunciation assessment for word-level accuracy (optional)
• Expo Router API route + Vercel AI Gateway for the coaching text
• MMKV for local storage
• SF Pro Rounded and Hugeicons Pro for the UI

Getting started

You need a development build. Expo Go cannot run this app, because speech recognition and MMKV need native code.

bun install
cp .env.example .env.local   # then fill in the keys
bunx expo run:ios            # or: bunx expo run:android

The iOS Simulator has no speech recognition. Use a real device to test a full session, or set EXPO_PUBLIC_MOCK_PRACTICE=1 to run the UI against a fake session engine.

Environment

Variable	Required	Purpose
AI_GATEWAY_API_KEY	For AI coaching	Server-only key for the coaching API route
AI_COACH_MODEL	No	Defaults to google/gemini-3.5-flash-lite
EXPO_PUBLIC_AZURE_SPEECH_KEY	No	Word-level pronunciation scoring
EXPO_PUBLIC_AZURE_SPEECH_REGION	No	Azure region for the key above
APP_VARIANT	Local	development, preview, or production
HUGEICONS_TOKEN	Install	Needed to install the Hugeicons Pro packages

Without Azure, sessions still score. The app falls back to its own alignment of the transcript against the passage text.

Scripts

bun test          # pure-logic tests for history, stats, alignment, and WAV
bun run ios       # build and run on iOS
bun run android   # build and run on Android
bun start         # Metro only

Project layout

app/           Screens and routes (tabs, session flow, API route)
components/    UI components, grouped by screen area
hooks/         React state: sessions, history, coaching
lib/           Pure logic: scoring, stats, alignment, formatting
services/      Side effects: recognition, Azure, storage, history
constants/     Passages, drills, topics, colors, fonts, metrics vocabulary

lib/ and constants/ stay pure. They never import from services/, so the scoring math runs under bun in the test scripts.

License

MIT. See LICENSE.