In her book Oh My God: A Brief History of Profanity, Dr  Melissa Moore of Stanford University describes an interesting phenomenon: some patients with Alzheimer's disease or stroke are able to repeatedly swear even after they have lost the ability to speak
This is confusing: isn't swearing just talking
Ordinary words are stored in the upper regions of the brain, which control autonomous behavior and rational thinking, while swear words are stored in the lower regions of the brain, which are responsible for emotions and instinctive reactions.