AI Language App Development (iOS & Android)

I need a skilled mobile team to turn my concept for an AI-driven language learning platform into two polished, production-ready apps for iOS and Android. The core experience revolves around a customizable ChatGPT-powered character that speaks aloud while displaying real-time transcription, letting users practise natural English conversation, take quick quizzes, and enjoy interactive storytelling sessions.

For launch, the learning content is limited to English, but I’d like the architecture left open so additional languages—Spanish and Chinese—can slot in later without major rework. If you have creative ideas on how to weave in progress tracking or a light gamification layer, I’m open to proposals; I haven’t settled on a final approach there yet.

I will provide brand assets, sample dialogue scripts, and access to an OpenAI account for the Realtime/Voice API keys. You handle everything else—from UI/UX and front-end React Native or Flutter code (your choice) to the backend services that coordinate user profiles, subscription handling, and analytics.

Deliverables
• Universal iOS & Android builds, App Store / Google Play ready
• Complete source code in a Git repo with clear commit history
• Documentation covering setup, API usage, and future language expansion
• A short demo video showcasing conversations, quizzes, and storytelling in action

Please outline your preferred tech stack, relevant AI or voice projects you’ve shipped, and an estimated timeline broken into logical milestones.