When National Geographic caught up with Byrne at her home in London, she explained why humans aren’t the only primates that can curse and why, though women are swearing more today than before, it is still regarded by many as “unfeminine.”

My first memory of being punished for swearing was calling my little brother a four-letter word, twat, which I thought was just an odd pronunciation of the word twit. I must have been about eight at the time; my brother was still pre-school. My mother froze, then belted me round the ear. That made me realize that some words had considerably more power than others, and that the mere shift in a vowel was enough to completely change the