Press Windows + X and select or Terminal (Admin) .
Once you have the .cab file on your offline PC (via USB drive), follow these steps: windows 10 english language pack offline installer
There is no official single "Offline Installer" executable. To install offline, you must , mount it on the target machine, and attempt to apply the language pack via DISM or by running the setup executable within the sources folder. Press Windows + X and select or Terminal (Admin)
For full localization (keyboard, date/time formats), also install: mount it on the target machine