Given the mix of traditions (Portuguese, African, Cuban, Brazilian) that make up Cape Verdean music, and the size of the expat market in the United States, it’s surprising no one has fully pursued a fusion of Cape Verdean sounds and American r & b until now. Making like a laid-back, island-dwelling Jill Scott, the Lisbon-born Tavares cranks up the bass and acoustic guitars and does some singing in English. Homogeneity mars the effect, but Tavares’ approach suggests a promising avenue for the future. Download: “Bue.” (Appearing Saturday at Berklee Performance Center.)