Rankin's original song "In the Name of Love" frequently featured wordless improvisational singing and showed his range and command of articulating lyrics at a blistering waltz tempo, but performed more slowly it had a distinctly Brazilian flavor. Similar to later singer Mandy Patinkin, Rankin's speaking voice was a rich baritone, but his tessitura was an octave higher, with an occasional start at near his speaking timbre, as in "What Matters Most." The timbre of his singing voice most frequently resembled that of a clarinet. His remarkably quick mastery of the guitar allowed him to appear, along with Randy Newman and Joni Mitchell, as one of the few self-sufficient solo acts conveying original material with harmonic richness beyond that of folk and early rock music.