synaps18, great question!
Today, only Amazon Alexa device (Echo, Tap, Echo Dot) can change language to Deutsch. Third party device is not capable yet. We will work on that and please stay tuned.
How to change Echo/Tap/Dot language settings?
- please log on your Amazon account at: alexa.amazon.com
- from the "settings" menu, find your device, click it
- change language from the language menu item
It can be done at Alexa app as well.