And in any case, "this concept is untranslatable" is nonsense, usually born out of xenophobia or jingoism. "MY language is more expressive than those OTHERS."

Every language has technical words that "cannot be translated." But when we say "cannot be translated," what we mean is "it is unsafe to expect a foreign reader to know what the term means without explanation." It's not that it can't be translated; it's that there isn't necessarily a single-word equivalent. I agree with the original suggestion that these can be a challenge to translate elegantly. But, speaking as a lawyer by training, the solution is obvious: you begin your technical document by describing novel technical terms. Then you use them in your document without explanation.

Consider "sushi": how do you translate that? Nowadays, we don't. But before it was widely known, you could've just said "a sour rice dish" and be done with it. (For those of you thinking "no wait, sushi is raw fish," no. That's sashimi. Sushi is vinegared rice mixed with other stuff, often. (Sushi can be with egg, pickled plum, crab, beef, etc. none of which are fish.)

Makizushi = rolled sour rice

Nigirizushi = sour rice to be gripped

Chirashizushi = sour rice with stuff scattered in it