Not that long ago a (male) friend of mine and I went on holiday to the Harz in Germany. Funny enough we ended up in a hotel of a Dutch-Surinamese couple for most of the time. So a plenty of Dutch was spoken, also among each other. Sometimes with a particular accent, as my friend and I are both able to speak (and understand) a Dutch version of Low Saxon.
Overall we got mixed reactions, mainly funny, when people heard us speak Dutch or the Low Saxon version.
Some young men asked us if we came from Bavaria, hilarious. They explained that it wasn't standard German we were speaking, but that we sounded (very) familiar. That was something we have heard from several others also. Various others could place us very easily, due to various reasons. The (older) owners of a restaurant we visited recognized the language as they had family living (and working) in the Netherlands and have had several Dutch guests. We also met German tourists who recognised the Dutch and Low Saxon based on the dialect/ regional language they grew up in. F.e. some people from Ostfriesland.
I have to confess I have the same with several other Germanic languages, they sound familiar but most of the time I can't understand them (with major exception of German and English, which I have had at school for several years & use at work).
Often you can understand a few words. F.e. in Norway we quickly picked up (tusend mal) tak.
English: (a thousand times) thanks
Dutch: (duizendmaal) bedankt / dank
German: (tausendmal) Danke
Danish: (tusinde) tak