Strategies for clarity help the receiver decode the message and to understand it quickly and completely. In the visual domain, clarity strategies span the whole gamut of visual language, everything from typefaces to charts to illustrations. If it doesn't that element lacks conciseness. Word choices often reveal your attitude toward your readers and your subject. Through your tone of voice you can sound serious, humorous, excited, flippant, formal, glum, concerned, technical, and so on.
Tone plays a crucial role is building ethos.
In screen design the variances in tone can be extreme, ranging from visually frenetic to serious. In any communication the speaker or writer tries to establish a trusting relationship with the listener or reader. To do that, the sender of the message needs to cultivate a sense of character or credibility that will appeal to the audience. Visual language also needs to build trust. Sometimes, credibility is historical, based on the reputation of the speaker.