To ensure the login screen and new user accounts also use the new language, go to Region > Administrative and use the "Copy settings"

Correction: For pure offline, you need the actual CAB file. The most reliable source is the .

: Third-party community archives host original ISOs, such as the Windows Server 2012 R2 Language Pack with Update (approx. 3.6GB) and the Windows Server 2012 Language Pack .