Windows 8 / Windows Server 2012 have changed a lot of UI. The old way for installing a dedicated language pack (lp.cab) does not work any more.
To do the same thing as before, you may love this: \Windows\system32\lpksetup.exe
Source: http://social.technet.microsoft.com/Forums/en-US/w8itproinstall/thread/ef9eada9-2abe-4d3e-8b8f-f66da098e651