One of the elders I worked with on my mission was Australian and his companion was American, and he kept a notebook every time he used a phrase his companion didn't understand. Then he'd check definitions with all of us.
"So what do you call a witch's hat?"
"A hat that a witch wears?"
"No, you know - on the road. A witch's hat. It's, like, the cone, you know, for traffic?"
"Um... a traffic cone?"
"You American Gumbies are so unimaginative."