Bug Snapshot
Context added for the language-switch issue shown in the screenshot.
Issue Context
The full conversation input was in English, but the assistant switched language in the middle of the response.
Expected Behavior
If the user writes in English, the response should stay in English unless the user asks to switch language.
Actual Behavior
The response started in English and then changed language part-way through.
Impact
This breaks response consistency and makes benchmark evaluation harder, because language drift can be confused with reasoning quality issues.