Swearing Is Good for You. By Emma Byrne. W.W. Norton; 240 pages; $25.95. Profile Books; £12.99.

IN THESE potty-mouthed times, when certain world leaders sling profanity about with abandon, many observers naturally lament the debasement of speech. But instead of clutching pearls, why not find a silver lining? Learning more about when, how and why people swear offers insight into everything from the human brain to a society’s taboos. Trash talking even affords some real physical and social benefits, as Emma Byrne argues in “Swearing Is Good for You”. 

For all their shock value, swear words are practical and elastic, capable of threatening aggression or coaxing a laugh. Among peers, profane banter is often a sign of trust—a way of showing solidarity with a larger group. Critics may say such language reveals boorish thinking or a limited vocabulary, but swearing is often impressively strategic, and a fluency in crass language typically correlates with verbal fluency in general.

Because the language learnt in infancy has the greatest emotional resonance, swearing in your mother tongue always feels most powerful, even among the most fluent multilinguals. As swearing functions as a complex signal, subtle enough either to amuse or to offend, these words vary according to what a culture deems unmentionable. Russian, for example, “has an almost infinite number” of ways to swear, most of them involving the honour of your mother. As for Japanese, because the culture is largely free of an excretory taboo (hence the poo emoji), there is no equivalent of “shit”. Yet the word kichigai (loosely translated as “retard”) is usually bleeped on television. Translators often struggle to render curse words and insults in other languages, as their emotional heft tends to be culturally circumscribed. For example, Westerners were more amused than alarmed by reports of an Iraqi minister declaring “A curse be upon your moustache!” to a Kuwaiti diplomat in 2003.

Women who curse face a double standard. Although swearing in a male-dominated profession can be a short cut to acceptance, women are also more likely to be shunned or seen as untrustworthy—even by women—when they sound like stevedores. This is not only because women are expected to be more polite than men, Ms Byrne suggests, but also because swearing tends to be associated with sexuality. Since women are judged more harshly than men for their sexual adventures, bad language leads to assumptions of bad behaviour.

Stoicism in the face of pain may seem noble, but swearing a blue streak is apparently more helpful. A study of volunteers forced to plunge their hands in ice-cold water found that those who swore kept their hands submerged for longer than those who were stuck bellowing a neutral word. By making people feel more aggressive—and therefore, perhaps, more powerful—swearing seems to improve the tolerance of pain.

A self-described swearing evangelist, Ms Byrne is certainly bullish on the merits of bad words. But in her eagerness to prove how “fucking useful” they are, she sometimes overplays her hand. She argues that swearing makes people less likely to be physically violent, but offers little evidence to back this up. She commends the way piss-taking can help people work together more effectively, but largely overlooks the way this approach can alienate minorities. She also occasionally trades empiricism for hyperbole, as when she declares: “I don’t think we would have made it as the world’s most populous primate if we hadn’t learned to swear.”

Still, “Swearing Is Good for You” is an entertaining and often enlightening book. It may not quite stand up the bold claim of its title, but Ms Byrne’s readers are sure to come away with a fresh appreciation of language at its most foul.