A tongue twister is a phrase which is difficult to say, especially when repeated multiple times in rapid succession. In 2013, a team of researchers at MIT decided to find the hardest tongue twister — and they succeeded. What did they come up with?
Pad kid poured curd pulled cod.
… While that phrase is meaningless, the study had a more serious mission. The lead researcher was a psychologist from MIT who studies who how brain glitches manifest in our speech.