Language & WorldFact
English imported 'Schadenfreude' because it had no word of its own.
English uses dozens of German words unchanged: Schadenfreude, Wanderlust, Zeitgeist, kitsch, doppelgänger, angst, kindergarten, rucksack, poltergeist, gesundheit (after a sneeze). Many fill a gap where English has no compact term. Some shifted meaning on the way: in English 'angst' means specifically existential dread, not just any fear.
Useful: Feel free to use these words in English; they read as educated, not as mistakes.
Source: en.wikipedia.org