Hi everybody,
the Polish language pack is available for front end, admin panel and setup:
http://exchange.oxid-esales.com/Shopping-process/Languages-Countries/Language-pack-Polish-4-7-7-Stable-CE-4-7-x.html
This language pack was developed in our translation center by @jmatos, @la bete, our Polish partner @makolab, @mart, @pawelch and @topconcepts.
For installation and more information about language handling please see
Good luck!