Twenty years ago, a charming little musical called “The 25th Annual Putnam County Spelling Bee” became a sleeper success story, earning a pair of Tony Awards, including one for best book, and providing a showcase for then-rising stars such as Jesse Tyler Ferguson and Celia Keenan-Bolger.

“Spelling Bee” is now being revived off-Broadway, and director Danny Mefford has tapped into a new generation of game, gifted young performers, among them two recent Tony nominees, to revisit the adorably motley crew of students vying for glory in the titular competition. Rachel Sheinkin’s slightly tweaked libretto retains additional material by Jay Reiss and room for the actors to improvise; at a recent preview, references to Mayor-elect Zohran Mamdani and AOC drew cheers from the youthful crowd.

But this show’s central appeal lies in watching a type of child who has persevered through generations — intellectually precocious but socially awkward — field the challenges posed by any such contest and by adolescence in general. “Spelling Bee” offers a number of amusing variations on this idea, all of them very funny and ultimately endearing.

There’s Marcy Park, a bundle of productivity who speaks six languages — not five, as a hostess announces before Marcy corrects her — but nonetheless insists, “I’m not all business,” projecting a fetching vulnerability in Leana Rae Cocepcion’s portrait. Reigning champion Chip Tolentino, whose unlikely haplessness is engagingly channeled by Philippe Arroyo, is stymied by an ill-timed fit of lust that becomes the subject of composer/lyricist William Finn’s most uproarious number here, performed as he tosses candy into the audience.

Audience participation plays a prominent role in “Spelling Bee.” Before each performance, volunteers are recruited to be “spellers,” then given instructions and invited onstage to provide fresh comedic material for the two actors playing the grownups overseeing the competition: one Vice Principal Douglas Panch and Rona Lisa Peretti, the hostess and the object of the vice principal’s unrequited adoration.

Played with winning wryness by, respectively, Lilli Cooper and Jason Kravits, they get some of the funniest lines in introducing characters, commenting on their interaction — as sportscasters would during a game — and accommodating their requests to have words defined and, especially, used in sentences. “Sally’s mother told her it was her cystitis that made her special,” Douglas quips at one point.

At another, asked to provide context for “phylactery,” after defining it as “either of two small square leather boxes containing religious texts traditionally worn on the left arm and head by Jewish men during morning weekday prayers,” Douglas offers, “Billy, put down that phylactery—we’re Episcopalian.”

Justin Cooley, who won deserved praise a few years back playing a sensitive teenage boy in the musical “Kimberly Akimbo,” brings just as much warmth and a wonderfully breezy goofiness to the part of Leaf Coneybear, who turns up only because the winner and first runner-up of another contest had to attend a bat mitzvah; but he emerges as a dark horse, at least for a while.

The more patently lost Olive Ostrovksy — deserted by her mother, who has gone to India on a spiritual quest, and left by her preoccupied father without money to pay for her participation — is played by Jasmine Amy Rogers, fresh off her starmaking turn in Broadway’s “Boop! The Musical.” Anyone lucky enough to have caught Mr. Rogers in that blazing performance may have trouble recognizing her here, bespectacled, dressed like a frump (by Emily Rebholz, whose costumes are all fun and evocative), and moving with a reluctance that suggests an urge to disappear into her surroundings.

The sweetest element of this “Spelling Bee” may be the bond that slowly but surely forms between Olive and a chap named William Barfée. Where Olive seems to want to hide, the nasally and emotionally congested William, played by a hilarious and moving Kevin McHale, would camouflage his insecurity with haughtiness, and the joyful connection that Ms. Rogers and Mr. McHale forge between these square pegs is nothing short of heartwarming.

You’ll likely find yourself rooting, in fact, for all the young people featured in “The 25th Annual Putnam County Spelling Bee” — both the characters and the actors who bring them back to the stage in this delightful revival.