[BUG] Claude generates unnatural Japanese compound words by literal translation from English

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Code sometimes generates unnatural Japanese expressions by
constructing compound words through literal translation from English,
rather than using established Japanese terms.

Claude Codeが、確立された日本語の複合語を使わず、英語からの直訳で
不自然な日本語表現を生成することがある。

What Should Happen?

Example / 例

Generated (unnatural) / 生成された（不自然）: 再試します
Correct Japanese / 正しい日本語: 再試行します（"retry"の定訳）

"再試します" is grammatically parseable but sounds unnatural to native
Japanese speakers. The established compound word "再試行" exists and
should be used instead.

「再試します」は文法的には解釈可能だが、日本語ネイティブには不自然に
聞こえる。「再試行」という確立された複合語が存在しており、そちらを
使うべきである。

Error Messages/Logs

Steps to Reproduce

Check the operation to return the example sentence

例示した文例を返す操作で確認する

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

4.6

Claude Code Version

2.1.49

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_