Tom Scott is on a language kick, which is great, because there's always more to learn about the way we communicate. Here, he tells us about the International Phonetic Language (IPL), which no one can read, but it's a standard used to communicate pronunciation across different languages. But that's not really what the video is about. It's about the sounds we make when we speak, and some that we don't. The sounds he says are impossible may present a challenge to you, so go ahead and give them a try.