Claude Code unexpectedly switches output language from Korean to Japanese mid-response

Description:
While working in a Korean-language conversation, Claude Code suddenly switched
its output language to Japanese mid-response without any prompt or instruction
to do so. The conversation was entirely in Korean, and the system instructions
explicitly set Korean as the response language. The switch happened during a
technical analysis section within the same response.

Expected behavior: Claude Code should maintain the configured response language
throughout the entire conversation.

Actual behavior: Output language switched from Korean to Japanese mid-response
during code analysis.

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.1.39
• Feedback ID: 0735ee95-9655-48b8-aeee-5ae2fcc745df

Errors

[{"error":"Error\n    at vk (/$bunfs/root/claude:42:1144)\n    at <anonymous> (/$bunfs/root/claude:43:10097)\n    at emit (node:events:92:22)\n    at endReadableNT (internal:streams/readable:861:50)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/claude:45:2149)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T00:58:39.429Z"},{"error":"MaxFileReadTokenExceededError: File content (30736 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T01:02:39.369Z"},{"error":"MaxFileReadTokenExceededError: File content (33476 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T01:03:01.366Z"},{"error":"MaxFileReadTokenExceededError: File content (30736 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T01:03:16.720Z"},{"error":"MaxFileReadTokenExceededError: File content (59898 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T01:03:17.378Z"},{"error":"MaxFileReadTokenExceededError: File content (63523 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T01:03:17.782Z"},{"error":"MaxFileReadTokenExceededError: File content (63544 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T01:03:18.173Z"},{"error":"Error: Request was aborted.\n    at oGR (/$bunfs/root/claude:865:99149)\n    at next (native:1:11)\n    at ssB (/$bunfs/root/claude:5705:4480)\n    at next (native:1:11)\n    at esB (/$bunfs/root/claude:5710:7793)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T01:31:02.340Z"},{"error":"MaxFileReadTokenExceededError: File content (33476 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T01:52:18.571Z"},{"error":"MaxFileReadTokenExceededError: File content (33476 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-11T01:52:23.324Z"},{"error":"MaxFileReadTokenExceededError: File content (33476 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at processTicksAndRejections (native:7:39)","t…

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