Not this moment. They have plans to make one big file for the backoffice.
What you can do is make a new directory into your language directories
and call this german. copy all the files from the english directory
Then you can download this file:
German
and overwrite the files. But you have to compare with notepadd ++ .
On the adminsite you have to make a new language add-on localization -->language
Directory:
/administrator/components/com_oscommerce_personal/languages/german
Hope this helps. It's the knowledge of oscommerce.