I often tell people to think of this the same way we treat copy guidelines. Every project where we think about, “If a brand were to speak to us, what would it say?” we also need to start thinking, “If a brand were to move, what would it feel like?” Is it whimsical? Is it swift and powerful? Is it a subtle added detail that helps users recognize who exactly you are? Demonstrating your tone of voice leaves your users with these little moments where they feel like saying, “I could totally see this brand doing that” because it felt so right and appropriate.