The UK’s Lady Sovereign is on the verge of making a serious imprint on hip-hop. With her double time flow, cheeky raps and unmistakable voice, this leader of the grime movement proves to be virtually incomparable to any other MC. The only downside of her American debut, the extended EP called “Vertically Challenged,” is the sparseness of new material. However, notable remixes by Menta and the Beastie Boys’ Ad Rock give new life to previously heard tracks. If Lady Sovereign plays her cards right with her upcoming full-length debut, she may very well dethrone M.I.A. as the UK’s most adored female export.