User Configuration > Administrative Templates > Microsoft Office 2016 > Language Preferences > Display Language
User
HKCU\software\policies\microsoft\office\16.0\common\languageresources
This policy setting controls whether users can install language accessory packs for Office even if they don’t have local administrator permissions on their devices. By default, users must have local administrator permissions on their devices to install language accessory packs. If you enable this policy setting, users will be able to install language accessory packs for Office even if they don’t have local administrator permissions on their devices. They can install those language accessory packs by going to File > Options > Language in the app, such as Word. If you disable or don’t configure this policy setting, users who don’t have local administrator permissions on their devices won’t be able to install language accessory packs. Someone with local administrator permissions on the device will need to install the language accessory packs for the user. For more information, see https://go.microsoft.com/fwlink/p/?linkid=2161939.