Why I Started Building TangoBox

Description and use

TangoBox is an Android app for Japanese learning that stores vocab, tracks progress, offers quizzes, and runs a local LLM, enabling offline study.

Problem

I couldn’t find a Japanese learning workflow that matched my study style—needed offline vocab saving, quizzes, progress tracking, and AI support.

Outcome

TangoBox provides a customizable, offline Japanese learning experience with vocab management, quizzes, progress tracking, and a Japanese‑focused LLM, all available on Android without ads or subscriptions.

Workflow

• Define learning goals and study style
• Design offline data storage for vocab and progress
• Implement quiz generation and tracking
• Integrate a Japanese‑focused LLM (downloadable locally)
• Add optional Gemini API key support
• Publish on Google Play without ads or subscriptions

Evidence

I wanted something where I could save words while studying, review them later, take quizzes, keep track of what I was actually learning, and continue studying even when I didn’t have an internet connection.

Source

The chat model can also be downloaded to the device once, allowing the learning experience to continue without an internet connection.

Source