The MUI package for Microsoft Office Communicator 2007 R2 is available as a free download and supports 38 languages. The installation is language-independent, so you do not need to first install the English version as a base, before you can install a MUI pack.

After installation, the user can change the language on demand (Tools—> Options –> General).

 

http://blogs.technet.com/chitpro-de/archive/2009/03/30/multilingual-user-interface-package-f-r-microsoft-office-communicator-2007-r2.aspx