I want to build a self-hosted online testing platform for language proficiency and competitive exams. The entire system must use only open-source, forever-free libraries and frameworks. No paid APIs, no usage-based services, no SaaS dependencies. The platform will be hosted on my Linux VPS (Hetzner) and should be scalable. Core Functional Requirements 1. Speech Processing (Self-Hosted) Record user speech via browser Store audio securely Convert speech to text (STT) Analyze: Pronunciation accuracy Fluency Grammar & spelling Content relevance Generate automated scores 2. Read Aloud Test Show a paragraph on screen User reads aloud Match spoken words with displayed text Score based on accuracy, pronunciation & fluency 3. Repeat Sentence / Audio Speaking Test System plays an audio clip User repeats it Compare spoken response with original reference Auto-score similarity 4. Supported Languages English French Spanish German 5. Question Types MCQs (text / image / audio / video) Fill in the blanks Dropdown questions Reorder sentences/paragraphs Essay / writing tasks with AI-based evaluation 6. Exam Features Timers (section-wise & question-wise) Word counter Highlight grammar & spelling mistakes Auto-save responses 7. Admin Panel Create/edit exams Add/edit questions Upload audio, image & video Configure scoring weightage 8. Compliance & Constraints Open-source libraries only Fully self-hosted No paid APIs (Google, OpenAI, Azure etc NOT allowed) Clean, documented, modular code Docker-based deployment preferred Preferred Developer Skills Python (FastAPI / Django) Speech Recognition & NLP AI model integration Online exam platforms Open-source deployment