The way we use words, their pronunciation and tone, all play a very important part in how well we understand each other. Even the slightest slip can lead to unexpectedly funny results.

Recently, I was giving one of my classes an individual speaking exam, in which students had to have a conversation with me for about five minutes. Things were going smoothly, until one of my students said: "I can't sleep. I live in a documentary."

I blinked, and she continued, "And I share it with five other girls."