In "Your Brain is More than a Bag of Chemicals," neurobiologist David Anderson of the California Institute of Technology establishes a tone from the outset of his presentation:
So raise your hand if you know someone in your immediate family or circle of friends who suffers from some form of mental illness. Yeah. I thought so. Not surprised.
And raise your hand if you think that basic research on fruit flies has anything to do with understanding mental illness in humans. Yeah. I thought so. I'm also not surprised. I can see I've got my work cut out for me here.
His words and manner are informal, conversational. Based upon the characteristics of his audience and the purpose of his talk, he sets a tone that engages his listeners and advances his purpose.
It's a sound strategy.
Tone is the author's demonstrated attitude toward subject, audience, and self, the mood or emotional approach of a talk or written piece. Every piece takes a tone, which means that a speaker or writer needs to take conscious control of its construction. That can be done in several ways, all of them aligned with audience needs, primary purpose, and the speaker's perspective.
Tone is in great part created by the level of formality used.
Anderson's relatively informal style includes colloquial language and very little of the jargon that would be familiar to his fellow research scientists. When he does use such terminology, he defines it in common, everyday terms.
He also includes sentence fragments and rhetorical questions at times. He uses contractions. He directly addresses his audience by using "you" and occasionally interrupts himself with a comment that serves as an editorial. And he uses "I," lending to the tone a more personal and subjective perspective.
DICTION, DETAILS, AND DESCRIPTION
The words a speaker or writer chooses to use contribute to tone. In order to be exact, they do need to capture the intended literal meaning. But they can also reflect connotations that express a richer or more evocative image than denotation allows. Thus Anderson uses the phrase "as if the brain were indeed a bag of chemical soup" to describe what he believes to be "an oversimplified and increasingly outmoded view of the biological basis of psychiatric disorders."
The choice of details can also support development of the desired tone. In this piece, the speaker creates a comparison between diagnostic techniques for cancer and those for psychiatric disorders. The comparison is likely to resonate with the audience and serves the speaker's purpose of explaining a hypothesis that differs from the prevailing one.
Whether written or spoken, language carries tone. But spoken, in-person language has the added elements of voice, facial expression, and body language with which to convey tone. These elements enliven delivery and make meaning more easily comprehensible but also help the speaker maintain a consistent tone.
David Anderson's tone is serious but playfully so. He smiles. He provokes laughter. But there is no doubt that he knows his subject and takes it seriously, that he respects his audience and wants its members to understand what he understands.
A writer or speaker can create any kind of tone—enthusiastic, somber, hostile, sympathetic, friendly—and it's a good rhetorical strategy to do so. Word by word, detail by detail, moment by moment in delivery, tone is one of many tools of effective communication, one to keep well in hand and use mindfully. Your audience will then indeed hear it.