I am from Flemish/Belgian origin, I understand the text but I can't understand Polish (I used Google Translate to understand your request on the comments "Mam taką prośbę, jeżeli ktoś z oglądających zna język holenderski i chciałby się podjąć tłumaczenia tego filmu poprzez wklejenie napisów to byłabym bardzo wdzięczna.") - I am from West-Flanders.
Maybe we could try a relay translation? If you are able to translate the original text into English, I could prepare a Polish translation based on it. A little bit risky but positively challenging as well, isn't it? :) How about, let's say, the first 10 minutes, as a starter?
It is interesting that the folk group from Wilamowice which travelled to Belgium, was singing (at least here in this video) exclusively in Polish, even though before (in Poland) they sung in their local germanic language. It is quite possible, that the communist authorities gave this condition: you can go to present 'our Polish culture', and presenting regional, German/Dutch origin language and songs, was actually forbidden to them. Still, the language seems more German than Dutch to me, with a strong Polish influence on phonology.
