Hi,
I don't have the problem on my end.
Did you install the German language file for HikaShop ? Not just Joomla's ?
If not, you need to go in the HikaShop configuration page, under the Languages tab, and click on the icon for your language. That will redirect you to a page with an alert message saying that it retrieved the language file, and you can then click on save to get the German translations for HikaShop.
If that's already done, I would recommend you activate the "debug language" setting of the joomla configuration page. At the bottom of each page, you'll see the debug information for the language files. So you'll be able to see if Joomla found HikaShop's German language file, and if so, it will also tell you if it found any errors in it, and if so, it will tell you on which line the errors are.