The requests and other documents being transmitted shall be accompanied by a translation into the Polish language or into English or French; the translation of the documents which are to be transmitted is not necessary if the transmission has the form of a simple service. In other cases they shall be translated into the Polish language if the receiver is a Polish national or if his permanent residence is in Poland. Where there is reason to believe that the addressee does not understand the language in which the document is drawn up, the document, or at least the important passages thereof, must be translated into Polish in the territory of which the addressee is staying. If the authority by which the procedural document was issued knows that the addressee understands only some other language, the document, or at least the important passages thereof, must be translated into that other language.