Intelligent Language Learning Platform with AI-Powered Assessment and Personalized Learning Paths
LexiLingo is an enterprise-grade language learning platform that leverages artificial intelligence and machine learning to provide personalized, adaptive learning experiences. The system employs a microservices architecture with specialized services for assessment, recommendation, and real-time interaction.
Key Capabilities:
- AI-driven language proficiency assessment (CEFR-aligned)
- Deep learning models for fluency, vocabulary, and grammatical analysis
- Adaptive learning paths with real-time progress tracking
- Gamified learning experience with achievement systems
- Multi-platform support (iOS, Android, Web)
LexiLingo implements a microservices architecture with clear separation of concerns:
┌─────────────────────────────────────────────────────────────────┐
│ Client Layer │
│ (Flutter - iOS / Android / Web) │
└──────────────────────────┬──────────────────────────────────────┘
│
↓
┌─────────────────────────────────────────────────────────────────┐
│ API Gateway Layer │
│ (Load Balancing / Routing) │
└──────────────────────────┬──────────────────────────────────────┘
│
┌───────────────┼───────────────┐
↓ ↓ ↓
┌──────────┐ ┌──────────┐ ┌──────────┐
│ Backend │ │ AI │ │ DL │
│ Service │ │ Service │ │ Model │
└────┬─────┘ └────┬─────┘ └────┬─────┘
│ │ │
└───────────────┴───────────────┘
│
┌──────────┴──────────┐
↓ ↓
┌──────────┐ ┌──────────┐
│PostgreSQL│ │ Redis │
│ │ │ Cache │
└──────────┘ └──────────┘
Backend Service (FastAPI)
- User authentication and authorization (JWT)
- Course management and curriculum delivery
- Progress tracking and analytics
- Gamification engine (XP, achievements, leaderboards)
AI Service (FastAPI)
- Language assessment engine
- Conversational AI integration (Google Gemini)
- Speech-to-Text and Text-to-Speech processing
- Real-time feedback generation
DL Model Service
- Fine-tuned Qwen 2.5 model for language analysis
- Fluency scoring algorithms
- Vocabulary complexity assessment
- Grammatical error detection
Client Application (Flutter)
- Cross-platform native experience
- Offline-first architecture
- Real-time synchronization
- Responsive UI/UX design
- CEFR-aligned Proficiency Testing: Automated language level assessment (A1-C2)
- Multi-dimensional Analysis: Fluency, vocabulary, grammar, and pronunciation scoring
- Adaptive Question Generation: Dynamic difficulty adjustment based on performance
- Real-time Feedback: Instant error detection and correction suggestions
- AI-driven Learning Paths: Customized curriculum based on proficiency and goals
- Spaced Repetition System: Optimized vocabulary retention algorithms
- Progress Analytics: Comprehensive learning metrics and insights
- Adaptive Content Delivery: Dynamic lesson difficulty and pacing
- Experience Points (XP): Progress-based reward system
- Achievement Badges: Milestone recognition and motivation
- Streak Tracking: Daily engagement monitoring
- Leaderboards: Competitive learning environment
- Conversational AI: Practice with AI tutors powered by large language models
- Speech Recognition: Real-time pronunciation assessment
- Interactive Exercises: Multiple question types and formats
- Multimedia Content: Audio, visual, and text-based learning materials
- Multi-tenant Architecture: Scalable for institutions and organizations
- REST & WebSocket APIs: Real-time data synchronization
- Offline Support: Local caching and background sync
- Analytics Dashboard: Detailed learning insights and reporting
| Component | Technology | Purpose |
|---|---|---|
| API Framework | FastAPI | High-performance async APIs |
| Database | PostgreSQL 14+ | Relational data storage |
| Cache Layer | Redis | Session management and caching |
| Authentication | JWT | Secure token-based auth |
| ORM | SQLAlchemy | Database abstraction |
| Migration | Alembic | Schema version control |
| Component | Technology | Purpose |
|---|---|---|
| LLM | Qwen 2.5 (Fine-tuned) | Language analysis and generation |
| Framework | Unsloth | Efficient model training |
| Inference | llama.cpp (GGUF) | Optimized model serving |
| Conversational AI | Google Gemini API | Interactive tutoring |
| Speech Processing | Whisper / TTS APIs | Voice interaction |
| Component | Technology | Version |
|---|---|---|
| Framework | Flutter | 3.24+ |
| Language | Dart | 3.8+ |
| State Management | Provider | 6.1+ |
| Dependency Injection | GetIt | 8.0+ |
| Local Storage | SQLite | Latest |
| HTTP Client | Dio | 5.0+ |
| Component | Technology | Purpose |
|---|---|---|
| Containerization | Docker | Service deployment |
| Orchestration | Docker Compose | Multi-service management |
| CI/CD | GitHub Actions | Automated testing and deployment |
| API Documentation | OpenAPI/Swagger | Interactive API docs |
LexiLingo/
├── backend-service/ # Core backend API service
│ ├── app/
│ │ ├── core/ # Configuration and security
│ │ ├── models/ # SQLAlchemy ORM models
│ │ ├── routes/ # API endpoints
│ │ ├── schemas/ # Pydantic schemas
│ │ └── crud/ # Database operations
│ ├── alembic/ # Database migrations
│ └── tests/ # Backend test suite
│
├── ai-service/ # AI and ML service
│ ├── api/ # FastAPI application
│ ├── models/ # ML model artifacts
│ ├── config/ # Service configuration
│ └── scripts/ # Utility scripts
│
├── flutter-app/ # Cross-platform client
│ ├── lib/
│ │ ├── core/ # Core utilities and DI
│ │ ├── features/ # Feature modules
│ │ │ ├── auth/ # Authentication
│ │ │ ├── learning/ # Learning sessions
│ │ │ ├── course/ # Course management
│ │ │ └── user/ # User profile
│ │ └── main.dart # Application entry
│ └── test/ # Flutter test suite
│
├── DL-Model-Support/ # Deep learning pipeline
│ ├── datasets/ # Training datasets
│ ├── scripts/ # Training scripts
│ ├── export/ # Model export utilities
│ └── docs/ # Model documentation
│
├── scripts/ # Development scripts
│ ├── setup-all.sh # Environment setup
│ ├── start-all.sh # Start all services
│ └── stop-all.sh # Stop all services
│
└── docs/ # System documentation
├── architecture.md # Architecture overview
├── api/ # API documentation
└── guides/ # Development guides
- Python 3.11+
- Flutter SDK 3.24+
- PostgreSQL 14+
- Docker & Docker Compose (optional)
# Clone repository
git clone https://github.com/InfinityZero3000/LexiLingo.git
cd LexiLingo
# Setup all services
bash scripts/setup-all.sh
# Start all services
bash scripts/start-all.sh| Service | URL | Documentation |
|---|---|---|
| Backend API | http://localhost:8000 | http://localhost:8000/docs |
| AI Service | http://localhost:8001 | http://localhost:8001/docs |
| Flutter Web | http://localhost:8080 | - |
# Build and start all services
docker-compose up -d
# View logs
docker-compose logs -f
# Stop services
docker-compose downInteractive API documentation is available via Swagger UI:
- Backend API: http://localhost:8000/docs
- AI Service: http://localhost:8001/docs
Authentication
POST /auth/register Register new user
POST /auth/login User login
POST /auth/refresh Refresh access token
GET /auth/me Get current user
Learning
GET /courses List available courses
POST /learning/lessons/{id}/start Start lesson
POST /learning/attempts/{id}/answer Submit answer
POST /learning/attempts/{id}/complete Complete lesson
GET /learning/courses/{id}/roadmap Get progress
Assessment
POST /ai/assess/fluency Analyze fluency
POST /ai/assess/vocabulary Assess vocabulary level
POST /ai/chat Conversational interaction
The system follows industry best practices:
- Clean Architecture: Clear separation of concerns
- Domain-Driven Design: Business logic isolation
- SOLID Principles: Maintainable and extensible code
- Repository Pattern: Data access abstraction
- Dependency Injection: Loose coupling
- Static Analysis: Automated code quality checks
- Unit Testing: Comprehensive test coverage
- Integration Testing: End-to-end API testing
- Code Reviews: Mandatory peer reviews
- CI/CD Pipeline: Automated testing and deployment
See CONTRIBUTING.md for development guidelines and coding standards.
| Document | Description |
|---|---|
| Architecture | System architecture and design |
| API Reference | Complete API documentation |
| Development Guide | Setup and development workflow |
| Git Workflow | Git branching and commit standards |
This project is licensed under the MIT License. See LICENSE for details.
- Issues: GitHub Issues
- Discussions: GitHub Discussions
- Documentation: Project Wiki
LexiLingo - Intelligent Language Learning Platform