Flip-flop sandals are staples of a summer wardrobe. However, experts warn this popular footwear can cause permanent damage to the feet and legs. If foot pain. Jul 28, - Now, the VOA Learning English program Words and Their Stories. “Flip-flop” is the sound the shoes make when you walk in them. But another way we use the word "flip-flop" in American English has nothing to do with shoes.