Switch the interface language

Ritsu has two surfaces with separate language settings: the interface (menus, buttons, settings pages) and the AI responses (what /explain, /quiz, etc. produce). They're independent.

Change the interface language

1. Open Settings → Profile → Language.
2. Pick English or Tiếng Việt.
3. Click Save. The page reloads; everything you see in the chrome (sidebars, settings, menus) switches.

That's it for the interface. Your saved content (decks, notes, quiz history) stays in whatever language it was originally in.

What about AI responses?

By default, AI responses follow your source language (the language of your PoK / source material), not your UI language. Why: if your textbook is in English, you almost always want explanations in English even if your UI is Vietnamese — preserves terminology.

To override per-session, run /lang in the chat:

/lang en        # English responses for this session
/lang vi        # Vietnamese responses for this session
/lang auto      # back to source-detection (default)

The override sticks until you /clear, switch PoKs, or sign out.

To force a permanent UI + AI match

In Settings → Profile → Language, check the box Also use this language for AI responses. With that on, every chat opens with /lang <ui-lang> already applied. Useful for monolingual study sessions.

Languages we support today

Language	Interface	AI responses
English	✓	✓
Tiếng Việt	✓	✓
Other	—	The AI handles dozens of languages — just write in them and it follows. The UI only ships EN + VI for now.

More UI languages are tracked on our roadmap. Vote with email to support@ritsu.ai if there's one you need.

Tips

• Search (Cmd+K) finds articles in either language regardless of your UI setting — it's diacritic-stripped Vietnamese-safe.
• Source language detection is automatic per upload. You can override per source from the source's settings.