The spoken word (unlike the written which can be reread) must be completely understood as it’s being heard. There’s no room for even a single gap. If the listener does not understand––even momentarily––the listener will stop listening. Unlike the written word, the spoken word is heard, not seen. That means visualization of what’s being described has to take place in the minds of those listening. If your words are not physical––palpable, corporeal––they can too easily become lost in the air.
He considers well before-hand the Subject he is about to enter upon; whether it requires to be explained only, or demands Proof like-wise; or whether needing both these, it doth besides interest the Passions of the Hearers. To judge rightly hereof, he substitutes himself in the Place of his Hearers: If one should arise before me to speak upon this Point, saith he, what would I expect? Explanation, Arguments, Pathetic, Imagination. He proceedeth accordingly.
The optic nerve is thick––unlike the ear’s vestibulocochlear nerve which is slightly over 1 mm in diameter––easily capable of receiving and processing large amounts of data: “Its diameter increases from about 1.6 mm within the eye to 3.5 mm in the orbit to 4.5 mm within the cranial space.” Thus, extra care and attention is required when communicating verbally in deference to the body’s innate anatomical bias in favor of sight as opposed to hearing.
If his Subject be a complex one, he weighs the several Parts of it distinctly; here he expounds, there argues, again affects; in another Place, softens the Rigour of Reason and Tumult of Passion with the gayer Colours of Fancy. He is always pure, clear, and harmonious in his Style; and is more especially attentive to suit it to the Occasion : It seems to spring from his Subject, and the Words wait ready, without his Industry, to cloath his Thoughts, as fast as they rise in his Mind. He is plain and modest in proposing; distinct and accurate in unfolding; weighty and pressing in confirming; in the Application touching, warming, penetrating. He is close, connected, full of Dignity and Energy in Reasoning; clear and distinct in explaining; lively and short in relating; exact, though concise, in describing; quick, rapid, animated in Passion.
Miscommunication explains many, perhaps most, social flaws and imperfections. We take for granted the person we’re speaking to understands what we’re saying. But if we’re off by even 10% that’s enough to change the meaning of the entire message. In court, there can be no room for miscommunication. Things can be taken out of context––misunderstood, misinterpreted––requiring more words to correct or clarify.
He mingles the Fire of the Poet with the Simplicity of a Philosopher, and the grave Majesty of the Historian; is sparing of Digressions, easy in Transitions, accurate in Comparisons, weighty in Reflexions. Never more artful than in concealing Art. Seeming most natural, where most skilful; most easy, where he had laboured most; correct with Spirit; entertaining with Solidity; with seeming Liberty observing always strict Method; never appearing to wander, but in order to make his Return more effectual; nor seeking to please, but with a View to persuade. Still gratifying your Curiosity with somewhat new, yet still keeping it up by a Prospect of more; ever rewarding your Attention, at the same Time redoubling it. At every Step, as in the ascending a high Hill, he presents to you a new Prospect, with a Glimpse of more, opening behind. Thus still satisfied, still unsatisfied, you are led from Expectation to Expectation, and remain in Suspence, until you arrive at the Summit, the Close and winding up of all; from whence you see the Scheme compleat, one just, well-conducted Whole; and the Mind entirely acquiesceth in it.
John Lawson was lecturing to a different audience in an earlier time, but his insights still hold true today. “He substitutes himself in the Place of his Hearers”––thus the question: what do they need to know and how can the message best be expressed so they can easily understand it? “Softens the Rigour of Reason and Tumult of Passion with the gayer Colours of Fancy”––a clear statement that the best way to make something stand out is by contrasting it against a lighter background. “Seeming most natural, where most skilful; most easy, where he had laboured most”––this explains the best speakers. They make it look easy, and it is, but only because they’ve paid the price––in hours. “He is plain and modest in proposing; distinct and accurate in unfolding; weighty and pressing in confirming; in the Application touching, warming, penetrating”––this succinctly encapsulates the mechanics of persuasion, where the initial presentation is precise and factual, and only later, after the facts have been established, assertive and argumentative. “At every Step, as in the ascending a high Hill, he presents to you a new Prospect”––yes, the vistas unfold in the telling, each with its own perspective. You just have to show the way.
All quotations from John Lawson, Lectures Concerning Oratory, Pgs. 223-225 (1972 Southern Illinois University Press)(Edited by E. Neal Claussen and Karl R. Wallace)(some, not all, spellings modernized)
 Wikipedia, Optic Nerve, https://en.wikipedia.org/wiki/Optic_nerve