Language, Timothy!
I think this may work.
Start|All Programmes|Microsoft Office|Microsoft Office 2010 Tools|
Microsoft Office 2010 Language Preferences|Add additional Editing Language|select German.
(English(UK) will be your default one)
If that doesn't do it, you will need a language Pack at £24.95.
PS Just found something else. Click on the Review tab, Translate, Mini Translator. Not sure that will do it, though.