The primary official source for businesses to download the "Language Pack ISO" and "Features on Demand ISO".
If you prefer the command line or need to script the installation, use the Deployment Image Servicing and Management (DISM) tool: Open PowerShell as an Administrator. windows 10 21h2 language pack download offline
For full system UI translation (including login screen), also download the from the Microsoft Store or install the matching FOD (Features on Demand) .cab . The primary official source for businesses to download