Download the language pack files ( .cab files) for the extra language you want to add.
Here's the step-by-step guide to offline install a Microsoft Windows 10 language pack: Microsoft Windows 10 Language Pack Offline Install -Extra
Use the DISM tool to install the extra language pack. The command is the same as before: Download the language pack files (
Create a new folder on your device to store the language pack files. For example, you can create a folder named LanguagePack in the C:\ drive. Microsoft Windows 10 Language Pack Offline Install -Extra
Copy the downloaded language pack files ( .cab files) to the new folder you created.