HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\MUI\Settings

Force selected system UI language to overwrite the user UI language
- HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\MUI\Settings\MachineUILock
Restricts the UI language Windows uses for all logged users
- HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\MUI\Settings\PreferredUILanguages