How to Install Additional Language Packs
Go to Start Menu - Tools - and click the 'Windows Update Service On' Shortcut.
Go to Settings - Network & Internet, and turn on 'Metered Connection'
Go to Settings - Time and Language - Language and Region, and click the 'Add a Language Button'.
✨If you install a language pack, and it gives you an error, your PC will restart a few times, then return to normal. To fix the error, Reboot, then remove the added language from the language list in the Settings App, Then re-install it, and it will work normally, and you will be able to use it as your System Language.