Offline installation modifies the system image. You run Command Prompt or PowerShell as an Administrator.
dism /online /add-package /packagepath:C:\Path\To\LanguagePack.cab Microsoft Windows 10 Language Pack Offline Install -Extra
Dism /Online /Add-Package /PackagePath:"C:\Path\To\your_language_pack.cab" Offline installation modifies the system image
Or via DISM:
If the UI is in the new language but search or spellcheck isn't working, you likely missed the Features on Demand (FOD) packages. 1.4.1, 1.5.8 Microsoft Windows 10 Language Pack Offline Install -Extra
Offline installation modifies the system image. You run Command Prompt or PowerShell as an Administrator.
dism /online /add-package /packagepath:C:\Path\To\LanguagePack.cab
Dism /Online /Add-Package /PackagePath:"C:\Path\To\your_language_pack.cab"
Or via DISM:
If the UI is in the new language but search or spellcheck isn't working, you likely missed the Features on Demand (FOD) packages. 1.4.1, 1.5.8