Freshly signed to Jay-Z’s Def Jam Left (also new home to the Roots), 19-year-old British grime MC Lady Sovereign is 5 foot 1 like Iggy Pop, and almost as cocky. She’s also poised to blow up next year. Her brief teaser of an EP, Vertically Challenged (on Chicago indie Chocolate Industries), is out this week and it’s full of catchy, dynamic electro-funk marked by grime’s trademark Richter-Scale bass blurges and liberal smatterings of video-game FX. Sov projects a playfully mischievous persona and possesses a passel of tart putdowns. She’s a more adept rapper than M.I.A. and cuter than Dizzee Rascal, plus she has Jay-Z’s clout behind her, so her forthcoming album looks likely to make a serious impact on the pop landscape. Prepare to be thoroughly sick of her by this time next year.