Everybody knows that different cultures speak different languages. But although their languages may sound different, different cultures have a similar experience being human, so they all need words to describe the same things. Most languages have a word for love, anger, hunger, envy, greed, grass, trees, the sky, god, etc. because we are all human, and we all share common experiences that we need to be able to communicate.
The German word for "love" is "Liebe." These two words sound different, but they mean the same thing, just in 2 different languages. And when Arabs use the word "Allah" they don't mean a different God than Christians or Jews do. All of these 3 religions have the same origin, and are based on the same God. That's why Jerusalem is considered a holy city by all 3 of them. "Allah" is simply the Arab word for the English word "God" or the German word "Gott" or the Latin word "Deus."
But sometimes a culture has unique quirks, singular peculiarities or unique circumstances that other cultures don't share. And then that culture needs words to describe their unique quirks.
Ever heard of the Sami people, also known as the Lapplanders? Like the Inuit (or Eskimos) of North America, the Sami live very far north, in the Arctic Circle. But the Sami live in Europe, in northernmost Finland and Norway, farther north even than Alaska. The Sami language includes 180 different words for snow or ice, and about 1000 different words for reindeer. Why? Because they are nomadic reindeer herders, and reindeer and snow are important parts of their lives.
To the Sami, reindeer and snow are far more important than to a US American for example. That's why Americans only have a few words to describe and distinguish between snow or slush or ice. But to a Sami, his life may depend on knowing whether the snow is frozen or soft, wet or powdery, dirty or clean. So they have a lot of different words for it. Makes sense.
What does all that have to do with Schadenfreude? Well, even cultures that seem very similar to each other on the surface, like Germans and Americans, sometimes have peculiarities that they don't share with each other and is unique to only one of them. So only one of these two cultures feels the need to have a word for it. What the word describes may not be completely unknown in the other culture, but the other culture simply didn't feel the need to specify a distinct word for it, because it just didn't seem that important to them.
The German word Schadenfreude describes the feeling of joy at someone else's misfortune. It describes that feeling of happiness, when something bad happens to someone else. There is no word for that in the English language, but the closest English synonym might be "spiteful glee."
English speakers may not have their own special word for that feeling, but it certainly is not an unknown emotion, as Nelson the bully on The Simpsons regularly demonstrates, laughing and pointing at Bart, when something bad happens to him.
What does the existence of the word Schadenfreude tell us about Germans and their psyche? Are they more spiteful than the rest of the world? Do they enjoy someone else's misery more than people of other cultures do? Is spiteful mocking of other people an important part of what it means to be a German? Or is their language simply more descriptive?