Language & i18n

Supported languages

Language	--lang= value	LLM-translated
English	en (default)
Japanese	ja	Yes
Chinese Simplified	zh	Yes
Korean	ko	Yes
Russian	ru	Yes

Setting the language

Pass the --lang flag when launching deer or deerbox:

deer --lang=ja
deerbox --lang=zh

To force English on a machine whose system locale resolves to another language, pass --lang=en explicitly:

deer --lang=en

Detection priority

If --lang is not specified, deer detects the language automatically. First match wins:

1. --lang=<code> CLI flag — overrides all other sources, including system locale
2. CLAUDE_CODE_LOCALE environment variable
3. System LANG environment variable (e.g. LANG=ja_JP.UTF-8)
4. Default: English

What gets localized

• Dashboard UI strings -- labels, prompts, status messages, keyboard shortcut hints
• Generated PR titles and descriptions -- written in the detected language
• Branch names -- always stay ASCII English regardless of language setting

Contributing translations

The LLM-translated languages may contain errors or awkward phrasing. To improve a translation, edit the relevant language block in src/i18n.ts (for TUI strings) or packages/shared/src/i18n.ts (for shared strings like PR descriptions).