You need to unpack this to the directory where you installed your Gothic from GOG and agree to swapping the files which are already there with the new ones. I extracted the files containing the videos and audio dialogues in Polish and made them into a. I'm hoping GOG will soon add other language versions to both Gothic 1 and 2 beside English and German but in the meantime I've come with a small work-around. If it's ok with the mods, please maybe make this topic a sticky or suggest where I should link it so that more people can find it easily. The below message is in English and Polish.