Face it: Most Americans can't do a passable British accent.

It's just a fact of nature.

That holds true for virtually the entire cast of Walnut Street Theatre's wrong-headed, cloying, and unsatisfying production of Oscar Wilde's The Importance of Being Earnest, now playing through April 30 at the theater's Mainstage in Center City.

Absent a Meryl Streep, the leads seemed befuddled by the accent challenge and spent such an inordinate amount of energy cultivating outlandish, exaggerated verbal gymnastics they ended up sacrificing sense, meaning, intention, and subtext.

A romantic comedy of manners, The Importance of Being Earnest concerns a pair of young, aimless, wealthy men of leisure -- Algernon Moncrieff  (Daniel Frederick) and John Worthington (Jake Blouch) -- who resort to a deliciously silly brand of deception to court two aristocratic girls. (It would be unjust to call them women.)

The gals -- the adventurous  Gwendolen Fairfax (Lauren Sowa) and the sheltered fantasist Cecily Cardew (Alanna J. Smith) -- aren't especially beautiful or particularly intelligent, though they have some wit. Yet they are eminently desirable because they possess that most highly prized commodity in Victorian society, good breeding.

The Walnut Street production boasts good design and some great choreography by director Bob Carlton, a highly respected and experienced British director and playwright who won an Olivier Award for his West End production of his musical Return to the Forbidden Planet.

Yet Carlton and his cast can't quite pull it off.

In essence, they treat the material as though it were the stuff of mainstream sitcoms, a genre that  thrives on big performances. Sitcom jokes demand exaggeration and overemphasis, especially on punch lines.

But Wilde is an ironist, not a stand-up comic. Sure,  Earnest is chock-full of incredible humor, crazy situations, surreal dialogue, and the most extraordinary zingers in English drama. Wilde's flights of verbal fancy deconstruct Victorian codes of conduct by attacking them at their linguistic roots.

The only way to highlight the eminent absurdity of the characters' pronouncements is to downplay the jokes, not wield them like hammers.

Frederick  and the Barrymore Award-winning Blouch don't so much play characters as deliver outsize caricatures. Algernon, for one, comes off like a demented version of Hugh Laurie's lovable aristocratic twit Bertie Wooster from the TV adaptation of P.G. Wodehouse's Jeeves & Wooster. Sowa and Smith matched their costar in general silliness.

The only performers who had a solid sense of what Wilde wanted to accomplish were the (slightly) older actors, most notably Walnut Street veterans Peter Schmitz as Cecily's local vicar and  Mary Martello as Gwendolen's mother, Lady Bracknell. Unlike their costars, they didn't rush full steam into their lines. Martello veritably luxuriated in Wilde's words, delivering withering comments about marriage and the war between the sexes with understated precision.

And then there's the question of the audience. It seems American audiences don't respond to British irony. Perhaps turning The Importance of Being Earnest into a sitcom is the only way to appeal to our tastes. I may have been squirming in my seat, but the rest of the audience loved the production and roared with laughter from start to finish.

The Importance of Being Earnest. Through April 30 at Walnut Street Theatre, 825 Walnut St. Tickets: $20-$85. Information: 215-574-3550, 800-982-2787, or walnutstreettheatre.org.