We've been studying Norwegian expressions. One I learned is "i bunn og grunn," which means fundamentally or basically. Why do they have an expression for that? Because it rhymes: bunn / grunn. We don't have to say, for example, "you're eating me out of house & home" but we do because of the alliteration. I imagine a lot of expressions or idioms in any language come about because they are pleasing to say, that is, they contain rhyme, alliteration, or some other poetic trick.
Here's a couple of other expressions:
* å hoppe etter Wirkola, literally, to jump after Wirkola, is to have to follow a master. (Bjørn Wirkola, born in 1943, was a great Norwegian skijumper. At some point, Wirkola will become virkola & people won't get the reference)
* hipp som happ means it makes no nevermind, six of one, half a dozen of the other
* A couple come from the seafaring or knight world, where we are so far away from knowing what the words literally mean that they are almost no longer figurative language, but the meaning persists.
I love this stuff.
Bonus treat: the word for ginger in the South Indian language of Tamil is ingi; in Norwegian it's ingefær. I love that ginger kept its name for a thousand years from Sanskrit through Latin & French, to the present day, in languages & places so far apart. Ginger = Ingi = Ingefær