There is an even nicer word for dutch/german. slechtstschrijvende/schlechtstschreibende. Yes, 9 consonants in a row and you have to pronounce all of them like you are a beatboxer.
Yet I'm downvoted as usual the whole point of these shibboleths is that they're hard to pronounce but the LondonDerry/Derry example set forth is not hard to pronounce but based on cultural context anyone can call San Francisco "Frisco"