Hi,
The install package of HikaShop only contains the English language file. However, after the installation, when you go through the install wizard, HikaShop will install for you the other language files for the languages on your website.
Now, if you don't have the interface in your language for one reason or another, you can download the language file of your language here:
www.hikashop.com/download/languages.html
And manually upload it to the languages/xx-XX/ folder ( in your case you want to replace xx-XX by de-DE ) of your website via FTP and you'll get it.
