The document discusses the four facets of a brilliant brand voice: personality, tone, rhythm, and vocabulary. It explains that a brand voice needs to be differentiated, authentic, and reflective of the audience. Personality draws on the brand's values and purpose and sets the overall impression. Tone conveys feelings and moods. Rhythm enhances personality and tone through pace and pattern. Vocabulary refers to the words used in a way that matches the brand. The document provides examples of different brands' takes on these facets and emphasizes that developing a brand voice beyond just listing adjectives can strengthen a brand's communications and user experience.