Cross Dialect Tongue Twisters

[Gareth3]

I haven't seen Knives Out, but a reviewer said that an Australian actress had some difficulty saying "alt-right troll" while playing an American character - the American vowels in that phrase are hard for Australians to copy. That reminded me of a Doctor Who writer deliberately including the phrase "Judoon platoon on the Moon", because the Scottish actor had trouble with that vowel in the character's English accent. What are some other examples? I also remember an American accent coach getting clients to repeat "sorcerer, torturer, murderer" over and over again, but that's probably too simple to qualify.