What's German city got that Irish quarter hasn't? (6)
I believe the answer is:
umlaut
'german city got that irish quarter hasn't?' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
I cannot understand how the remainder of the clue works.
(Other definitions for umlaut that I've seen before include "Mark over some German letters" , "In German, written mark indicating change in vowel pronunciation" , "Two dots put over a vowel in German" , "Dots over letter (indicating vowel change)" , "Diacritical sign" .)