Translation:His children only eat pasta and meatballs.
This is a Swedish to English exercise though, not Swedish to German. Personally I've never seen an English-speaker call it "köttbullar", just "Swedish meatballs" (and the "Swedish" part is kind of implied already since it's translated from a Swedish sentence). I'm open for corrections though if any native English-speaker does call it by its Swedish name.
Interesting. When the noun sing and pl are the same, some languages will give you a clue from the verb endings. For example, 'the deer is in the road' vs. 'the deer are in the road'. But with Swedish, you can eat a whole meal of pasta and meatballs without figuring out how many children he has ...
Maybe, but usually when we eat meatballs with pasta in Sweden it's not the traditional large Italian ones in marinara sauce, but just the standard, slightly below golf-ball sized, Swedish meatballs fried in a pan, with the only sauce being ketchup. That's not too say that Italian meatballs don't exist in Sweden, but that if you're a working parent (as the vast majority of Swedish parents are) of small, picky children, as this task implies, then you'll be much more likely to put on some 3-minute macaroni and fry some pre-formed meatballs than anything more fancy.
My youngest son used to make a serious face and say, "I don't like this" every time we sat down to dinner. We would make him try it, and he ALWAYS liked what we were having. I decided to put a stop to it and one evening after we said grace I dished up food for his two older siblings, took some myself, and my husband put some on his own plate....and after a couple of minutes our youngest asked in a forlorn voice, "Can I have some?" Of course we gave him some, and he ate his dinner without a complaint. That was the end of the "I don't like this" nonsense. But oh my gosh, I almost cried doing that to him. I felt like such a mean mommy!
But of course he wasn't actually a picky eater. He always liked the stuff, no matter what it was. He just didn't like the way it looked, evidently. Or he wanted a little control over his world.
I imagine it is quite a different situation when your child really is a picky eater who won't eat certain things. Maybe your meatballs are just too delicious!
Note the two possible placements of "only":
1. He eats only pasta.
2. He only eats pasta.
Sentence 2 is probably what most English speakers would say most of the time. However, Sentence 1 is a bit more elegant because it is not ambiguous.
Sentence 2 is open to various other interpretations. He only eats pasta -- he does not do anything else at all. Or he only eats pasta, he does not build with it, etc.
I believe the Swedish here could only be interpreted like sentence 1 -- it's all the children eat but they do have other interests.