Sean Hepburn Ferrer and brother Luca Dotti have feuded in the past over multiple issues related to their mother—but the books they’ve written about her agree that Hepburn was one of a kind.

There’s a moment in the documentary Audrey: More Than An Icon that especially stands out. Audrey Hepburn’s eloquent, unmistakable voice—one that suggests its owner speaks more than one language (she ...