EchoTalk – Offline Shadowing Practice 🗣️

EchoTalk is a privacy-first, offline language training tool that helps you master the Shadowing technique for improving pronunciation, fluency, and confidence. It works as a Progressive Web App (PWA), requires no server, and keeps all your recordings securely on your device.

🔗 Live Demo: (alisolphp.github.io/EchoTalk)

🔗 Mirror Server: (alisol.ir/EchoTalk)

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✨ Features

🧠 Smart Training & Learning Modes

• Skip-Only, Check, and Auto-Skip modes for flexible practice styles.
• Auto Repetition & Auto Speed that adapt dynamically to your progress.
• Repetition counters so you always know how many loops are left.
• AI Personal Teacher:
  • Get fast, targeted analysis of your pronunciation & fluency (word-by-word guidance).
  • Generate context/nuance insights and creative practice (variations, opposites, Q&A, fill-in-the-blank) to remember meanings better and faster.

📝 Rich Content

• Large ready-made sentence packs organized by level and category.
• Personalized sample sentences by language, level, and topic.
• Word-level tools: click any word for meaning/pronunciation and AI-powered analysis.

🤖 AI Integrations & Extensions

• Grammar help, translations, and vocabulary expansion via AI.
• Creative exercises (opposites, variations, quizzes) with ChatGPT/Gemini prompts.
• Fast AI pronunciation analysis of your recordings (offline prompts supported).

🎨 Modern UI/UX

• Multi-language support: English, Dutch, Polish, Portuguese, Russian, Turkish, and more.
• Word-level interaction: click a word to open tools for meaning, pronunciation, and AI-powered analysis.
• Practice streak tracker with calendar view and motivational messages.
• History & recordings: review all your past practices and replay your recordings.
• Seamless flows: restart or switch sentences easily, plus celebration animations after sessions.
• Live recording visualizer for instant feedback.

♿ Accessibility

• Adjustable TTS speed (slow → furious).
• Keyboard-only navigation for mouse-free practice.
• Screen reader friendly with live progress announcements.

⚙️ Technology & Performance

• Works fully offline after first load.
• Optimized for Chrome & mobile browsers (with fallbacks for others).
• PWA with auto-updates and local caching for fast startup.
• Version & build info displayed in-app for easy bug reporting.
• IndexedDB storage for recordings and practice history.
• Service Worker caching for instant load times.

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🚀 Getting Started

1. Enter or pick a sentence (or use a personalized sample).
2. Choose your language, level, and practice mode.
3. Click Start Practice.
4. Enable microphone recording (optional).
5. Listen, shadow, and track your progress.

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🛠️ Technologies

• Vite + TypeScript
• Bootstrap 5 & Bootstrap Icons
• IndexedDB for offline storage
• Web Speech API (TTS)
• MediaRecorder API
• PWA + Service Worker
• Vitest for unit testing

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🧪 Tests

EchoTalk has 200+ unit tests covering:

• Practice logic and session flow
• State management and persistence
• Audio recording and playback
• IndexedDB integration
• UI event handling and DOM updates
• Utility functions (segmentation, similarity, text cleaning)

Coverage Summary

File	% Stmts	% Branch	% Funcs	% Lines
src/app.ts	72.48	71.42	80.95	72.48
src/types.ts	100	100	100	100
src/services/ai.service.ts	97.43	90.38	100	97.43
src/services/audio.service.ts	72.41	88.31	80	72.41
src/services/data.service.ts	84.83	78.48	78.26	84.83
src/services/practice.service.ts	76.75	77.14	72.72	76.75
src/services/prompts.service.ts	100	100	100	100
src/services/ui.service.ts	84.28	89.06	80.76	84.28
src/services/util.service.ts	92.68	88	100	92.68
src/utils/string.extensions.ts	100	100	100	100
All files	80.63	82.95	83.22	80.63

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📦 Installation

git clone https://github.com/alisolphp/EchoTalk.git
cd EchoTalk
npm install
npm run dev

Run tests:

npx vitest run --coverage

Build for production:

npm run build

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⚠️ Limitations & Browser Support

• Built-in Speech-to-text (STT) is not yet implemented.
• Best performance on Chrome & Android browsers.
• Safari and Firefox may have limited IndexedDB quota or recording issues.

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🧑‍🔧 Roadmap

• ✅ Multi-language support & sentence history
• ✅ Practice streak tracker with calendar
• ✅ AI integrations for grammar, translation, and pronunciation
• ✅ Offline-first with recordings saved locally

Next Up

• Custom Video & Subtitle Upload
• YouTube API Integration
• Explore & browse sentences by level and category
• Export tools for recordings
• Gamification (badges, levels, rewards)
• Community sharing features

🔮 Planned Enhancements

• Custom Video & Subtitle Upload

  • Users can upload their favorite movies or clips along with subtitle files.
  • Practice with content they love, in the exact accent they want to train.
  • Facial expressions and lip movements become part of the shadowing experience.

• YouTube API Integration

  • Let users pick and practice directly with YouTube videos.
  • Faster and easier than manual video + subtitle uploads.
  • ⚠️ Planned for the future due to API costs and potential complexity.

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🧑‍💻 Contributing

Contributions are welcome! You can:

• Report bugs
• Suggest features
• Improve code or docs

Fork the repo, make your changes, and open a pull request.

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📄 License

MIT License – see LICENSE.