If the system language changes after a firmware update on the Xiaomi Watch 5, please refer to the following troubleshooting steps:
1. After a firmware update, the watch will retrieve the phone’s language settings again, which can result in the system language changing automatically. Please confirm whether the phone language has been changed.
2. If the language is supported by the watch, the system language will change to match the phone. If the language is not supported, a pop-up will notify you that the language is not supported. Please select a supported language on the watch.
3. If the issue persists, please contact the after-sales service for further inspection.