Language.
At least we can read the signs here as the letters are familiar. Japanese kanji was not easy to read.
I spent two or three years studying German for 'O' level many moons ago. Our teacher was dreadful but the class was worse with many "challenging" pupils. Unsurprisingly, I was graded 'U' in the final exam. In my defence, so was the entire class.
But I do have a few words, and can understand a little more than I can speak.
I have a couple of very favourite words: Krankenhaus and Botschafter. They make me smile.
Tim has a new hobby - counting the number of letters in the crazily long words. His record sighting had 27 letters. But he can't remember the word.