http://www.bbc.com/future/story/20170126-the-untranslatable-emotions-you-never-knew-you-had

“Lomas says he was first inspired after hearing a talk on the Finnish concept of sisu, which is a sort of “extraordinary determination in the face of adversity”. According to Finnish speakers, the English ideas of “grit”, “perseverance” or “resilience” do not come close to describing the inner strength encapsulated in their native term. It was “untranslatable” in the sense that there was no direct or easy equivalent encoded within the English vocabulary that could capture that deep resonance.”