There have been several posts on this topic already. And after reading through them I now know how to change my landline voicemail to English. The rest refer to a page on the everything kmc site that is no longer linked or searchable. Does anyone know how to change the voicemail to English?
Thanks! 

I am trying to change my voice mail to English and have been told by TMobile they have no idea. Can anyone help me. 

Easy peasy lemon squeezy.

Dial 3311 to get into voicemail.
Listen to the spiel in German and then press 3 to get to "settings".
From there, press 4 to get to "other settings".
From there, press 1 to change language.
From there, press the star (*) key to change to English.
Hang up.
Redial 3311 and confirm the change worked.

This only works for T-Mobile BTW. 

Thanks for posting that Nicksdad, just changed mine to English.