After World War II, Theodore von Karman (Hungarian physicist, one of the founders of aerodynamics) gave lectures in Pasadena (California) and Aachen. This great scientist advised several airlines and could fly over the ocean for free on one of the aircrafts of such a campaign.
For an elderly scientist, such trips were sometimes exhausting, but the situation was saved by the fact that in Aachen and in Pasadena von Karman read very similar courses of lectures.
And one day, when he flew to Pasadena, von Karman took the Aachen Context and began his lecture. After some time in the faces of the students, he realized that the material did not reach them, and only then realized that he was reading the lecture in German.
Von Karman addressed the audience:
“Why are you silent?”
After a short pause, one of the students confessed:
“Professor, do not be upset! Whether you speak German or English – it doesn’t matter, we still don’t understand any more.”