Like fellow riddim & blues artist Sasha, Rihanna drops in and out of patois accidentally on purpose, usually coincident with the comings and goings of ’80s synth-pop delirium. Unlike Sasha, it’s hard to tell how much she’s copping generically Middle Eastern harmonies (though the Diwali-inspired dhol drumming is unmistakable even if I’ve never heard it doing a Bo Diddley before) and how much, like fellow dancehall divas Lady Saw and Gwen Stefani, she’s borrowing from Fiddler on the Roof. Better than Robbie Williams’s and Missy Elliot’s “Hey DJ” tracks, slightly worse than J. Lo’s, and just about matching Lil’ Wayne’s, “Pon De Replay” has Rihanna’s Jay-Z-approved voice chorused, cut, and overdubbed into a room-filling cavalcade of reflexive call and self-response. Rapper A.P. plays Big Tigger to her R. Kelly, offering up the generic square-dance calls: “Signal di plane like you tryin’ to get captured.” I wonder if he knows what bumbaclaat really means, but in the midst of this gleeful chaos (did I mention the synth-simulated airhorns? and the mildest hint of macarena?) such concerns hardly seem the point.