If you’re solving a German-themed crossword, the diacritical mark most commonly clued is UMLAUT. It appears in crosswords as 6 letters: UMLAUT. Details you can use:

• The umlaut is the two dots placed over vowels in German (ä, ö, ü) and changes the vowel sound.
• Common crossword clue phrasing: “A diacritical mark placed over a vowel in German to indicate a change in sound” -> UMLAUT (6 letters).
• Related terms you might encounter: DIAERESIS in other languages, but in German crosswords UMLAUT is the standard answer.

If you’d like alternatives for different letter counts or a few crossing- letter suggestions, share the intersecting letters and I’ll tailor possible fills.