One of the first things any article about sisu will tell you is that this Finnish word is untranslatable. (https://finland.fi/arts-culture/sisu-within-finnish-key-life-love-success/)
‘Sisu’ in Finnish means strength, perseverance in a task that for some may seem crazy to undertake, almost hopeless. (http://www.bbc.com/capital/story/20180502-sisu-the-finnish-art-of-inner-strength)
So, what’s going on here? The first source tells us that the word sisu is untranslatable, and then the second source goes on to translate it. Is it untranslatable? Is it even possible for a word to be untranslatable?
The redoubtable Joe McVeigh points us to a New Yorker article on this subject, an article that provides us a glossary of supposedly untranslatable words — complete with translations! What’s that about? McVeigh observes that
we can clearly translate these words. There just may not be a 1:1 translation for each of them. But as anyone who has ever done any translating will tell you, that’s so obvious that it barely needs mentioning. But there’s something else behind this idea and I want to open it up a little bit.
So let’s see what he does, and what we think of it. McVeigh cites a traditional example of a Finnish word that is supposedly untranslatable, bolstered by the following cartoon, which of course includes a translation (by this point, you’re beginning to get the point, so I’ll stop adding punctuation):
So yes, it can be translated. It just can’t be translated by a single English word: it takes a phrase. Anyway, that’s just an example, and you’ll want to read McVeigh’s thoughtful article to get a deeper understanding of the issue. It’s very thorough, so you may not want to read the entire article — but read enough to get the flavor. And kalsarikännit is not an activity I recommend.