Johnson links to a video of Baez singing Love is Just a Four-Letter Word with Earl Scruggs and his son on banjo and guitar. It's a treasure to see and hear, but the production values suffer, so here is the song taken from her 1968 album, Any Day Now: Songs of Bob Dylan.
And here she is singing forty years later at the Cambridge Folk Festival in 2007. The song, Diamonds and Rust, recalls the emotions of her two-year relationship with Bob Dylan during the mid-1960s. Still the voice on an angel.