I have only ever heard the story, but my grandma came over here from Germany after WW2 to marry my grandpa (American Army) after they met in Germany.
Anyway, they are driving and she is learning English and she gets horrified and says, “THEY SELL THAT HERE?!”
My grandpa turns the car around and drive back to read the sign which had “pups for sale”. Because she was German and the U is usually pronounced with an OOH sound, well…she quickly learned how to say “pups” in English.