I feel like most other comments are missing something important, the o3-pro thought process you see in the chatgpt ui is a summary. So although the model might

I feel like most other comments are missing something important, the o3-pro thought process you see in the chatgpt ui is a summary. So although the model might think in different languages, the summary (presumably done by a different model) will translate it into your UI language. It seems like this summarization AI messed up, and gave you some text in a different language.