CRM 2013: Base Language not showing

Hello

We installed "Update Rollup 5 for Microsoft Dynamics CRM 2013 Service Pack 1" last week, because we had several issues with UR 4.

- Base Language ist German.

- We installed additional the Language Packages for English, French and Italien.

Now we have one problem:

When we open CRM now, we have the most of the GUI in German (All Field Labels etc.). But also a lot of parts are in English (Menu, Navigation, Options etc):

What did we forgot?

Thanks

Raffi