In movies, lip reading always seems like a secret code that can be cracked with a little practice. On-screen lip readers catch every word of conversations taking place across a room. In reality, it’s a little more complicated. By some estimates, only about 30 percent of speech is visible by looking at people’s lips, and things like dim lighting, laughter, hand gestures, and accents can make it even more difficult.

A short film called “Can You Read My Lips?” explains just how hard it is to communicate in a world without sound. Rachel Kolb, who has been deaf since birth, stars in and narrates the video, based on her essay, “Seeing at the Speed of Sound.”

“The human face isn’t a book and lip reading isn’t reading,” she explains. Try to figure out what people are saying without listening to the sound in the video above.

Banner image screenshot via Vimeo