Most of us intuitively understand that there are differences between oral and written language. All communication includes the transfer of information from one person to another, and while the transfer of information is only the first step in the process of understanding a complex phenomenon, it is an important first step. Writing is a fairly static form of transfer. Speaking is a dynamic transfer of information. To be an effective speaker, you must exploit the dynamism of oral communication, but also learn to work within its limitations. While there is a higher level of immediacy and a lower level of retention in the spoken word, a speaker has more ability to engage the audience psychologically and to use complex forms of non-verbal communication
The written language can be significantly more precise. Written words can be chosen with greater deliberation and thought, and a written argument can be extraordinarily sophisticated, intricate, and lengthy. These attributes of writing are possible because the pace of involvement is controlled by both the writer and the reader. The writer can write and rewrite at great length, a span of time which in some cases can be measured in years. Similarly, the reader can read quickly or slowly or even stop to think about what he or she has just read. More importantly, the reader always has the option of re-reading; even if that option is not exercised, its mere possibility has an effect upon a reader’s understanding of a text. The written word appeals more to a contemplative, deliberative style.
Speeches can also be precise and indeed they ought to be. But precision in oral communication comes only with a great deal of preparation and compression. Once spoken, words cannot be retracted, although one can apologize for a mistake and improvise a clarification or qualification. One can read from a written text and achieve the same degree of verbal precision as written communication. But word-for-word reading from a text is not speech-making, and in most circumstances audiences find speech-reading boring and retain very little of the information transmitted.
On the other hand, oral communication can be significantly more effective in expressing meaning to an audience. This distinction between precision and effectiveness is due to the extensive repertoire of signals available to the speaker: gestures, intonation, inflection, volume, pitch, pauses, movement, visual cues such as appearance, and a whole host of other ways to communicate meaning. A speaker has significantly more control over what the listener will hear than the writer has over what the reader will read. For these techniques to be effective, however, the speaker needs to make sure that he or she has the audience’s attention–audiences do not have the luxury of re-reading the words spoken. The speaker, therefore, must become a reader of the audience.
Reading an audience is a systematic and cumulative endeavor unavailable to the writer. As one speaks, the audience provides its own visual cues about whether it is finding the argument coherent, comprehensible, or interesting. Speakers should avoid focusing on single individuals within an audience. There are always some who scrunch up their faces when they disagree with a point; others will stare out the window; a few rude (but tired) persons will fall asleep. These persons do not necessarily represent the views of the audience; much depends upon how many in the audience manifest these signals. By and large, one should take the head-nodders and the note-takers as signs that the audience is following one’s argument. If these people seem to outnumber the people not paying attention, then the speech is being well-received. The single most important bit of evidence about the audience’s attention, however, is eye contact. If members of the audience will look back at you when you are speaking, then you have their attention. If they look away, then your contact with the audience is probably fading.
Speeches probably cannot be sophisticated and intricate. Few audiences have the listening ability or background to work through a difficult or complex argument, and speakers should not expect them to be able to do so. Many speakers fail to appreciate the difficulties of good listening, and most speakers worry about leaving out some important part of the argument. One must be acutely aware of the tradeoff between comprehensiveness and comprehension. Trying to put too much into a speech is probably the single most frequent error made by speakers.
This desire to “say everything” stems from the distinctive limitations of speeches: after a speech, one cannot go back and correct errors or omissions, and such mistakes could potentially cripple the persuasiveness of a speech. A speaker cannot allow himself or herself to fall into this mentality. At the outset, a speaker must define an argument sharply and narrowly and must focus on only that argument. There are certainly implications of an argument that are important but cannot be developed within the speech. These aspects should be clearly acknowledged by the speaker, but deferred to a question-and-answer period, a future speech, or a reference to a work that the audience can follow-up on its own. Speakers must exercise tight and disciplined control over content.
As a rule of thumb, the audience will remember about one-half of what was said in a twenty-minute talk. After twenty-minutes, recall drops off precipitously. Oral arguments should therefore be parsed down as much as possible. There are very few circumstances in which an audience will recall a great deal of the information in a speech longer than twenty minutes. Most evidence suggests that audience recall declines precipitously after 16 and one-helf minutes.
Oral communication uses words with fewer syllables than the written language, the sentences are shorter, and self-referencing pronouns such as I are common. Oral communication also allows incomplete sentences if delivered properly, and many sentences will begin with “and,” “but,” and “except.”
The upshot of these differences is that one should not think about speeches as oral presentations of a written text. Speeches are genuinely different from written prose, and one should not use the logic of writing as a basis for writing a speech.