Much of the media narrative leading up to today's wedding of Prince William and Kate Middleton has focused on Kate's "commoner" background, particularly her mother's family, hailing from the humble coal-mining country of northern England. In class-conscious British society, differences in social background come through in speech patterns — as anyone who's seen "My Fair Lady" knows. So how have the royal family and the middle-class Middletons navigated this tricky linguistic terrain?

Kate's parents, Michael and Carole, are self-made millionaires, having set up a successful party-supply business. But when William and Kate began dating, after meeting as classmates at University of St. Andrews, stories began emerging from the royal circle about snobbery over the Middletons' less-than-aristocratic roots. Carole was particularly singled out for abuse, especially after she was seen chewing nicotine gum at William's military college graduation parade in 2006, in the presence of William's grandmother, Queen Elizabeth II.

The following year, the knives came out for Carole when it was reported that William and Kate had split up. Now the focus was on something more embarrassing than gum-chewing: Carole's middle-class speech, inappropriate when addressing the Queen. The London tabloids breathlessly reported (based on unnamed "Royal sources") that Kate was clearly not a good match for William because her mother used words such as Pleased to meet you, toilet, and Pardon?

Pleased to meet you, the tabloids explained, is a gauche way to greet the Queen, when Hello, ma'am is called for. Rather than toilet, one should say lavatory or loo. And when asking someone to repeat a question, middle-class Pardon? is frowned upon, in favor of a simple What? All of this might seem extremely puzzling to outsiders, but these class-based shibboleths do actually exist in British society (even if Carole's alleged gaffes might have been embellished as tabloid fodder).

The class differences trumpeted by the tabloids were first laid out in 1954, when the linguist Alan S.C. Ross introduced the terms "U and non-U" to describe English usage of the upper class and the aspiring middle class. Ross had published his article in an obscure journal, but the novelist and socialite Nancy Mitford (who came from a decidedly aristocratic background) brought "U and non-U" to wider attention in an essay she wrote two years later. Even then, Pleased to meet you, toilet, and Pardon? all made the "non-U" vocabulary lists of Ross and Mitford — indicative, they said, of unseemly social striving among middle-class speakers trying to appear more genteel.

Much has changed in Britain's social landscape in the last half century, and yet these class markers continue to persist. In a 2004 book entitled Watching the English: The Hidden Rules of English Behaviour, the social anthropologist Kate Fox lists "seven words that the English uppers and upper-middles regard as infallible shibboleths." Fox writes, "Utter any one of these 'seven deadly sins' in the presence of these higher classes, and their on-board class-radar devices will start bleeping and flashing." Pardon? and toilet lead off the list, followed by serviette (instead of napkin), dinner (instead of lunch, when referring to the midday meal), settee (instead of sofa), lounge (instead of sitting room or drawing room), and sweet (instead of pudding, for the sweet course at the end of a meal that Americans call dessert).

As the flap over Carole Middleton's supposed linguistic offenses showed, there are still lingering anxieties over how to "talk posh." Actually, as Fox explains in her book, "If you want to 'talk posh,' you will have to stop using the term 'posh,' for a start: the correct upper-class word is 'smart.' In upper-middle and upper-class circles, 'posh' can only be used ironically, in a jokey tone of voice to show that you know it is a low-class word." Got it?

As for Kate and William, any qualms over the class divide don't seem to have manifested themselves since their temporary breakup in 2007. (In the meantime, a more socially embarrassing relative of Kate has emerged: her dissolute uncle Gary, brother of Carole, who sports a "Nouveau Riche" tattoo across his shoulder blades.) It turns out that the couple and their circle are united in another kind of social grouping, known as rahs or yahs, roughly equivalent to American preppies. A recent Slate article lampooned the affluent ways of the rahs and how they stereotypically speak:

What is the rah patois? You must know our ding-a-lingo, darling. Everything is glorious, divine, splendid, beauteous, naughty, a twirling whirl. We adore archaisms: alas, anon, perchance. Never say evening. It's eve. Never say balsamic. It's balsam. Adorn everything with French. Je t'embrasse. Ce soir. Chez moi. I am a flâneuse. You are a flâneur. Let us troubadour ensemble. Bisous!

Bonded in rah-dom, perhaps Kate and William can steer clear of the social pitfalls of past generations, creating a new kind of prestigious talk to aspire to. In the meantime, if you happen to get an audience with William's grandmum, remember not to tell her you're pleased to meet her.

Click here to read more articles from Word Routes.

Ben Zimmer is language columnist for The Wall Street Journal and former language columnist for The Boston Globe and The New York Times Magazine. He has worked as editor for American dictionaries at Oxford University Press and as a consultant to the Oxford English Dictionary. In addition to his regular "Word Routes" column here, he contributes to the group weblog Language Log. He is also the chair of the New Words Committee of the American Dialect Society. Click here to read more articles by Ben Zimmer.

Not One-Off Britishisms
Ben Yagoda is keeping track of Britishisms creeping into American usage.
The British singer Susan Boyle brought the word "gobsmacked" to worldwide attention.
Crossing the Pond
The blog Separated by a Common Language takes on transatlantic differences.