In Swedish, öl means beer. In German, Öl means oil (and, being a noun, it’s always capitalized). However, in Turkish, öl is the stem and familiar singular imperative of ölmek, which means to die. Thus, if you’re Swedish and Turkish, beer will kill you, and if you’re German and Turkish, oil will kill you.
No further explanation is required to appreciate the humor, but I remember guffawing when I learned how to say “oil” in high school German class. Also, it might be worth noting that the Swedish and German words are pronounced with a long ö, while the Turkish word is pronounced with a short ö.