Unlikely on paper but effortless in execution, Vampire Weekend’s debut blends the teatime refinements of chamber-pop with the rhythmic imperatives of South Africa and Jamaica. Recorded while the ink was still drying on the band’s diplomas, the songs here track twentysomething life in ways that look out more than they look in: the upper-class girl who loves lower-class music (“Cape Cod Kwassa Kwassa”), discussions of privilege that touch equally on grammar and crunk (“Oxford Comma”), and plain old romantic apology (“I Stand Corrected”). Of course, they’re smart enough to know that smarts aren’t everything, so they make it catchy, too.