Hearing is a two-step process. First, there is the auditory perception itself: the physics of sound waves making their way through your ear and into the auditory cortex of your brain. And then there is the meaning-making: the part where your brain takes the noise and imbues it with significance. Mondegreens occur when, somewhere between the sound and the meaning, communication breaks down. You hear the same acoustic information as everyone else, but your brain doesn't interpret it the same way. What's less immediately clear is why, precisely, that happens.