The 25th Annual Putnam County Spelling Bee, Donmar Warehouse, London

The Broadway musical, as a habitat, tends not to throng with nature's great spellers. Gypsy's Mama Rose could probably get through "audition", without mishap, but the chances are that she'd put a middle "e" in "monstrous". And, even though it's her native German, how would Maria von Trapp cope with "Weltanschauung" – the word that happens to be the climactic clincher in The 25th Annual Putnam County Spelling Bee, a musical comedy (by William Finn and Rachel Sheinkin), that redresses the balance, to an almost parodic degree, in favour of the non-orthographically-challenged?

Receiving its English premiere in Jamie Lloyd's rumbustiously enjoyable production, the show pitches us Brits into the arcane alien rituals and anthropological bizarreries of the kind of tortuous, torturing contest for teenagers that seems designed to put the "eek!" in "geek". We're in a school gym. We're sponsored by local optometrists. There's a black, handsome "comfort counsellor" on community service (excellent Ako Mitchell) who longs to tell the nerdy little brain-boxes that "pain has degrees" and that losing here is as nothing ("but that would violate my parole"). Officiating over the event is blonde glamour puss Rona Lisa Perretti (spot-on Katherine Kingsley), a former winner whose blinkered romanticising of the proceedings is in hilarious contrast to the dog-eat-dog reality. And contributing to the pervasive sense of more-than-faint perviness is Steve Pemberton's sublime pronouncer-in-chief, who is there to deliver undermining introductions and to read out deadpan, deeply unhelpful sentences in which the usage of the word-to-be-spelt is demonstrated (eg "Billy, put down that phylactery. We're Episcopalian").

Spelling Bee is a dippy, spirited mix of the genuinely funny and gratingly fake. It's at its best when it's involving us in the technicalities. Members of the audience are invited to be participants and on the press night these included the actor Daniel Kaluuya (Sucker Punch). One of the most elating moments was when he managed to guess the correct spelling of that ancient Scottish whaling term: "catergunes".

By this token, I much preferred songs such "Magic Shoe" in which the fabulously fat and aggressively repressed William (superb David Flynn) gives terpsichorean expression to his method of tracing the words with his foot to the much more generic numbers about the family neglect, pressuring parents (one girl has "two dads") and stressful American Dream ("You hate losers/ So do I/ I'm a loser/ So goodbye") that have propelled the kids onstage. I expect that Mama Roses (or should that be Mamas Rose?) are a dime-a-dozen on this circuit ("Spell out, Louise!). But in assimilating the experience of these teenagers to the very different exhibition world of the Chorus Line humiliation-plus-inner-monologue format, the show reneges on its own wittiest insights. And the blanket happy ending is as phoney as hell. The piece lasts one hour 40 minutes and for the last half-hour I have to own to up to a sensation of satiety. "Sa-ti-e-ty. The feeling or state of being sated." Can I have a sentence, please? Yes, here it is. "Could it be because there's no interval, mother, that I feel full to satiety?"

To 2 April (0844 871 7624)