Picture the scene: several thousand people, gathered in a muddy field in Pilton, Glastonbury, singing along with a song about . . . an obscure punctuation mark. “Who gives a f*** about an Oxford comma?” is the catchy refrain from Vampire Weekend’s recent hit. It perfectly combines the picky pleasures of academia (the use of a comma before a grammatical conjunction, no less) with a two-fingered joie de vivre.

It’s a stance that has helped the Brooklyn four-piece to soar from internet novelties to proper world-touring pop stars this year. “The audience that day was incredible,” says the band’s singer, Ezra Koenig, cracking a slow smile. “That’s still the most people we’ve ever played to, so it was kind of a shock.”

He and his band colleague Rostam Batmanglij are sitting today outside a Brooklyn coffee shop, soaking up the last of the summer sun and reflecting on their year so far. And why, in particular, the Brits have taken Vampire Weekend to their hearts. They may have toured in Japan and Australia but it’s in Blighty that the band is biggest. “I think we all take inspiration from British pop music, though it’s a pretty diverse tradition,” Koenig says. Batmanglij nods. “I mean, ever since we started, we’ve had people saying they thought we were British.” His brow furrows. “Especially in France.”

It’s funny, because to look at Vampire Weekend, they couldn’t be more American; fresh-faced and sporting the kind of yacht-chic you would expect to see in a Ralph Lauren ad (today, Koenig is wearing beautifully tailored white shorts with a crisp T-shirt). The band formed at the Ivy League university Columbia in New York, and if their image is decidedly unrock, so is their conversation. It is not often you hear a doe-eyed young pop hero say: “I’m just interested to hear Milan Kundera’s theory of the novel.”

Lyrically, their songs glow with unusual illustrations, from the arcane (ions and cryptographs) to the exotic (pueblo huts, Dharamsala). Anything, Koenig says, to avoid emotional cliché. “People say Bob Dylan lyrics make no sense,” he says, “but you can spend a lot of time thinking about them – and you can’t do that with something that’s total nonsense. Almost anything is better than just repeating the tried and true feelings.”

So how have Vampire Weekend managed to go beyond the tried and true feelings? College books aside, the band’s real inspirations go far back. Koenig was brought up listening to Fela Kuti records, by Jewish parents with a penchant for Buddhism. Early memories include throwing a tantrum in a supermarket when surrounded by forbidden Christmas sweets, and realising early on that there was no Santa Claus. Batmanglij, too, says that as a kid he was sceptical of religion – though both have a deep-seated love of Christmas carols. “D’you know In Excelsis Deo?” Koenig, his eyes lighting up, “Ah aaaaah aaaaaah . . . ”

Raised in Washington DC, the young Batmanglij would demand every car journey be accompanied by the Beatles’ Taxman. He took up the flute at 8, and, he says, “made it cool at my school”. Batmanglij now writes film scores, and arranges the giddy string flourishes that whirl across Vampire Weekend’s songs. Koenig learnt classical piano, and played the sax in his high school marching band. Like Lisa Simpson? “Yeah,” Batmanglij says guffawing, “did anyone ever call you Lisa Simpson?” “No,” Koenig says flatly. The pair met at a party just after arriving at Columbia and immediately talked about starting a band. They were, Batmanglij says, part of the 20 per cent of kids at Columbia who actually socialised (“because the legal drinking age is 21, and a lot of people don’t even have fake IDs”).

So, the two started showing each other songs they had written. Bassist-to-be Chris Baio was waiting, literally, in the wings of a school production of Romeo and Juliet, in which Koenig and Batmanglij were acting (there are photos of the pair in costume as Night-watchman 1 and 2, on the web). Both Batmanglij and the drummer Chris Tomson were music majors, introduced at harmony class. “On that first day we met people who would go on to help us record our album,” Batmanglij says.

Vampire Weekend’s rather unremarkable first incarnation was as a folk-rock outfit. Then the band’s story took a surprising turn. The cardigan-toting Koenig had become a rapper and asked Batmanglij to help him to record his rap record. “I’d been rapping for a while, since high school,” he says, “and when I was a freshman these seniors got me really into freestyling.”

Freestyling, to the unacquainted, is when rappers set off on streams of consciousness, rhyming with whatever comes into their heads. It’s something you would associate with Jay-Z, not Vamp-We. Can you still do it? “If you get him high enough,” Batmanglij grins. “Freestyle battling gets the same brain waves going as when you’re writing a song.”

The pop-rap group, featuring Batmanglij and Baio, lasted until Koenig got sick of it and felt a need for live instruments. And so, Vampire Weekend was born – named after a spoof horror home movie Koenig made on vacation, in which he stars as an ordinary kid turned vampire slayer.

After graduating, Koenig taught English literature to inner-city kids in New York, while Batmanglij arranged music for films. And gradually, via recordings in friends’ basements and their own apartments, Vampire Weekend were born. Much has been made of their Afropop sound. There are chiming, reverbed guitars and high-pitched sweet melodies, and the band say they were listening to a lot of Madagascan pop at the time, even joking that the sound was “Upper West Side Soweto”.

When fellow New Yorkers Yeasayer emerged, with their rock-meets-tribal sound, and Vampire buddies Dirty Projectors introduced their fusion of King Sunny Adé and Black Flag, it seemed to be a case of what Brian Eno terms “scenius”, the communal form of genius. “Scenius?” Koenig ponders. “There are little connections there that have to do with living in the same area and being the same age,” he shrugs.

But the comment levelled at Vampire Weekend most is that they sound like Graceland-era Paul Simon. “It’s somewhat of a putdown to say that your band sounds like someone else’s album. Like, you can’t even move beyond one phase of Paul Simon’s existence,” Koenig says, frowning. “But then to other people, Graceland just means really good pop songs with some nonEuropean influences. It’s hard to know how to take it.”

The record does share a feeling with Graceland – a warmth, and a joy in being alive. And both records are imbued with a certain New Yorkiness – the “angels in the architecture” that Simon sung about in You Can Call Me Al suggested by Batmanglij’s celestial strings, and a just-off-the-boat fascination with the city’s nooks and crannies. But Vampire Weekend is a young album, the sound of a band at the start of their adventures.

As for the next step, Koenig admits he finds the idea of a second album stressful; little wonder, given the scrutiny of the past year. “There’s this cliché of the failed second album, and I can’t pretend it doesn’t cross my mind,” he says. “But then I get excited when I think about just making it, ’cause I know we’ll be happy with how it turns out.” Above all, Batmanglij says, “I don’t think we need to overthink it.” Leaving the café, the pair stroll together down the leafy avenue, fully aware that there’s a time to think deep thoughts and a time to just enjoy the sunshine. Lucky for us Vampire Weekend can do both.

Touring in the UK from Oct 20 (www.vampireweekend.com)

Explore Music

• CD Reviews

• Live Reviews

• Classical

Editor's choice

• The 100 Best Films of the Decade
• 70 facts you didn't know about Marvel
• The 50 Biggest Movies Of 2010