Guides

Make Claude Code reply in your language: the language setting and CLAUDE.md

Published November 5, 2026 · Last checked November 5, 2026

Claude Code replies in English by default. To get replies in your language, you have two documented options: a language key in settings.json, or a line in CLAUDE.md. This page shows both, which file to put them in, how to check that they loaded, and how to set the language of code comments and commit messages separately. It follows Anthropic's Settings reference and Memory pages, checked on November 5, 2026.

Option 1: the language setting

The Settings reference lists a language key that makes Claude respond in a language other than English by default. The value is a string: any language name, with "japanese", "spanish" and "french" as the documented examples. Anthropic says there is no fixed list for responses. The value goes to Claude as written, so any language name Claude can read works.

{
  "language": "japanese"
}

The key can go in any settings file: user ~/.claude/settings.json, project .claude/settings.json, local .claude/settings.local.json, or managed settings from your organization. Because the value is not validated, a misspelled name does not produce an error. It reaches Claude as written. The same value also sets the language for voice dictation and for auto-generated session titles. When it is unset, session titles match the language of your conversation.

Option 2: one line in CLAUDE.md

CLAUDE.md is the instruction file Claude Code reads at the start of a session. Anthropic lists three places for it:

• ~/.claude/CLAUDE.md: personal preferences for all projects, visible only to you.
• ./CLAUDE.md or ./.claude/CLAUDE.md: project instructions shared with the team through version control.
• ./CLAUDE.local.md: your own preferences for one project. Add it to .gitignore.

Reply language is a personal preference, so ~/.claude/CLAUDE.md is the natural home. Anthropic advises instructions concrete enough to verify, so spell it out:

- Always reply in Japanese.
- Keep code, commands, file names and identifiers in English. Do not translate them.

If your whole team works in one language, put the same lines in the project's ./CLAUDE.md. Everyone who pulls the repo gets them. To change the language for one project only, use ./CLAUDE.local.md, which is not committed.

Set code comments and commit messages on their own line

"Reply in Japanese" is about the conversation. The language of code comments, commit messages and docs is a separate choice. State it, so Claude does not have to guess:

- Reply in Japanese.
- Write code comments in English.
- Write Git commit messages in Japanese, in the form "type: summary".

This wording is our suggestion, based on Anthropic's advice to write concrete, checkable instructions. Short separate bullets are easier to follow than one dense paragraph, and Anthropic recommends headers and bullets for structure.

Check that it took effect

1. After editing, start a new session and run /context all. Look for your CLAUDE.md under Memory files.
2. Run /memory. It lists your CLAUDE.md, CLAUDE.local.md and other memory file locations across user and project scopes, and opens a file you select.
3. Ask a simple question in English and see whether the reply comes back in your language.

It is guidance, not enforcement

Anthropic says CLAUDE.md content is delivered as a user message after the system prompt. Claude reads it and tries to follow it, but strict compliance is not guaranteed, especially for vague or conflicting instructions. So:

• Do not write conflicting language rules in CLAUDE.md. Anthropic notes that Claude may pick one of two contradicting instructions arbitrarily.
• Keep it short and concrete, under 200 lines per CLAUDE.md file.
• For something that must always happen, do not rely on CLAUDE.md alone.

Through CoreCode, nothing changes

Both language and CLAUDE.md are settings of the Claude Code client. They live on your machine and in your repo. Connecting to CoreCode only changes where requests are sent, so these files are read as usual and you write them the same way as with a direct connection. For setup see the Claude Code guide, and for the full CLAUDE.md guide see How to write CLAUDE.md.

FAQ

Sources

• Claude Code: Memory (CLAUDE.md locations, CLAUDE.local.md, /context all, /memory, no guarantee of strict compliance; checked November 5, 2026)
• Claude Code: Settings reference (the language key and the settings files it works in; checked November 5, 2026)