Reticence and reflection, properly channeled, more urgently beckons the ear and the body to lean in closer than does all the flash and panache of a Broadway showstopper. Kentucky songwriter Joan Shelley traffics in this brand of quiet, and with guitarist/fellow Louisville resident/Alan Lomax archive curator Nathan Salsburg at her side, creates the sort of plaintive intensity that Oxford American Presents spotlight so adeptly. “I keep my songwriting alive and sustainable by trying to be honest about how it came out,” Shelley said in the pres release accompanying the show. “These are all its jagged edges, and that’s what it is to be human.” Shelley performs tonight at South on Main, 7 p.m.; get tickets here.