OT but as a German-speaking reader of the New Yorker this abuse of the Umlaut has been making me irrationally angry for decades. But it’s a nice reminder that if you want to, I dunno, capitalize only the word “Dog” and end every sentence in a comma, you might want to own a magazine, Dog,
The diaeresis is unrelated to the umlaut though, it's a notation borrowed from old Greek. It never quite caught on in English, but it's part of the standard orthography of many other languages.
