In Windows 10, users can set their system language to English while using a French keyboard layout, but there are challenges due to the dependency between keyboard layouts and language settings. When switching to a French keyboard, users may encounter issues, such as being unable to log in if their password contains characters that are mapped differently on the French layout. The keyboard sends scan codes to the computer, which then maps these codes to characters based on the selected layout. While Windows allows for changing keyboard settings, users report that the system may revert to default layouts, such as QWERTY, unexpectedly. To effectively use a French keyboard with an English language setting, users may need to explore specific settings or consider using a French-Canadian keyboard layout as a workaround.