Native dutch from the eastern part that has lived in the southern part too, now in Munich and knows (and speaks) quite a lot of dialects. This sounds like someone from Luxemburg would be better at understanding. It's a mixture of dutch spoken in Limburg (soft tones, not the "hard" r and g pronounciation that is typical for the western parts of the Netherlands) but also not that modern vlaams melody. I could understand it roundabout a sgood as when I hear someone speaking Afrikaans.

If it's any help, I speak pretty good dutch, some german, and some czech (which is similar to polish) and can only understand about 1/4 of this. Any native dutch speakers can feel free to chime in, but I don't think speaking dutch is a major advantage in understanding this.

I speak (Austrian) German and it sounds a lot more like a German dialect than Dutch to me (there are so many of them, though, this is not really saying an awful lot). Like the Dutch speakers who've chimed in, I don't understand much of it but can pick out enough words to tell where the other, incomprehensible words are.

It sounds like some Dutch farmer dialects. I cannot understand a word of it, but it surely does not sound anything like a slavic language to me.

The first fragment with the old woman sounds a bit more like Dutch or Low Saxon but with heavy German influence. The second clip with the young man sounds very much like a German dialect to me (Dutch native). Understanding either of them completely would take a lot of effort.

Sounded like "1+1 am Tag macht 2" at 4:33

2nd video: "Das sind die Sproech" "Da kann ich gehn, da kann ich meditieren, da kann ich alles machen" almost plain German. at 0:44 - 1:00

and many other German snippets

Afrikaans speaker here. Might as well have been Russian. Didn't get any of it.