Claude Caught Thinking in Polish When Answered in English

A Reddit user found that Claude's extended thinking process ran entirely in Polish despite an English-language query, switching back to English only for the final answer, sparking discussion about the unpredictability of models' internal reasoning languages.

2026-09-30 ~ 2026-09-30 · 2 related posts

• User asks Claude in English, model does its thinking in Polish — raoadithya · 2026-09-30
• User asks Claude in English, its chain of thought runs in Polish — Far_Designer2131 · 2026-09-30