Translation:The jellyfish leaves the flæskesteg in the kitchen.
...which is also the Scandinavian name of the zodiac 'Aquarius', btw.
The name for jellyfish is only Danish...in Swedish and Norwegian it's called 'manet' (usually 'glassmanet' indicating that it's glassy/transparent as opposed to the red/dark coloured thready & burning one, which is a 'brennmanet', literally "burning manet").
Revisiting this sentence after living in Copenhagen for three years, I can confirm flæskesteg is the same as what any British person would call "roast pork with crackling".
The standard trimmings may be different (red cabbage, boiled potatoes and brun sovs [= Danish gravy] instead of green veg, roasties and gravy) but there is nothing special about the word "flæskesteg" which means it needs to be preserved in the English sentence.
I guess there may be UK/US differences to account for, so "pork rind" should be considered as well as "crackling". But it is the whole skin cooked on the joint.
This is not the same as the small pieces of pork rind you may eat as a bar snack ("scratchings" in the UK) - they are called "flæskesvær" in Danish.
I agree...adopting local words like this might work in some cases, but definitely not in all. (Even using our local characters in English isn't really a good idea.)
I think Duo is using the word in order to teach some local culture/habits alongside the core language, and since the word usually refers to the entire meal, it's a bit tricky to translate it semantically perfect. However I'd probably say 'roast pork' or something like that. (It's not a filet, really, but a large single piece of pork meat, normally with fat on it, which is cut into slices. Closer to a big chunk of bacon or spare ribs type meat, but with no bones...might also be a piece of shoulder or thigh/ham with fat on it)
Sorry..."rind" was the English word I was looking for. The "flæskesteg" is supposed to have the rind on, and it should ideally be crispy and snacksy to eat.
In parts of Norway (mainly the South East part, i.e. around Oslo), it's also a traditional Xmas dinner, although must be a piece of the ribs with the bones left in the meat. In Norway, the cabbage is often not red (like sauerkraut in Germany), and there's typically no brown sauce with it, but only fat from the meat itself.
In both Denmark and Norway, it should be served with beer (preferably dark Christmas ale (close to brown ale) with around 6-7% alcohol, and also followed by Aqua Vita (locally called 'Akevitt') which is the Scandinavian schnaps (potato based spirits around 40% with lots of digestive spices, most notably cumin).