Dr. Tim Lomas, a professor at the University of East London, became fascinated by the way that some languages have words which just don't translate exactly into English. So he began compiling a list of them,. He also studied the way that English simply absorbed some of those words into itself and began using them to express those concepts they described in their native habitat.
As Dr. Lomas notes in a Scientific American article on his project, words referred to as "untranslateable" are such only if you insist on some kind of one-to-one correspondence between the words. Those words do translate, but it takes several words or even some sentences to do so. He gives the example of the German word Treppenwitz, which literally translates into English as "staircase wit." But it describes the great comeback or pithy comment that comes to you too late to be a good response in the conversation. If "translate" means only the one-to-one substitution mentioned above, then Treppenwitz doesn't translate. But since there is an English idea that it matches, then it does translate, but requires several words for that to happen.
Folks in my profession have to deal with this kind of thing a lot, because our primary source documents are in two distinct languages: Greek and Hebrew (there's a sprinkling of Aramaic in there as well). Modern Greek and Hebrew have words that struggle to cross over into English, which is bad enough. But we have to work with ancient versions of both languages, which are more or less not spoken today. However difficult it is to make connections between modern cultures with different languages, multiply that many-fold when one of the cultures involved hasn't existed for more than a thousand years.
A single word in Greek might require a paragraph of explanation in order to be adequately understood. And there are some Hebrew passages which translate just fine -- but they make no sense when they do, because those words aren't used that way any more (ancient Hebrew's lack of written vowels adds to the fun).
Of course, some of my colleagues insist on that as a license for their overly prolonged orations, but that's just mean in any language.