Speed
First, there is the speed of delivery. An angry woman can utter more words in a minute than any one wants to hear. The general principle underlying all speech delivery is that as the audience increases in number the rapidity of utterance should be lessened. Those who are accustomed to addressing large audiences, or to speaking in the open air, speak very slowly.
A second consideration is the material being delivered. Easily grasped narrative, description, and explanation, simply phrased and directly constructed, may be delivered much more rapidly than involved explanation, unfamiliar phraseology, long and intricate sentence constructions, unusual material, abstract reasoning, and unwelcome sentiments. The beginnings of speeches move much more slowly than later parts. A speaker who intends to lead an audience a long distance, or to hold the attention for a long time, will be extremely careful not to speak at the beginning so rapidly that he leaves them far behind.
"The beginnings of speeches move much more slowly than later parts."
This does not mean that a speaker must drawl his words. One of our national characteristics is that we shorten our words in pronouncing them—ing generally loses the g, does not has become doesn't and quite incorrectly don't, yes is yeeh, etc. In many cases nothing more is required than the restoration of the word to its correct form. Some words can easily be lengthened because of the significance of their meanings. Others must be extended in order to carry.
The best method of keeping down the rate of delivery is by a judicious use of pauses. Pauses are to the listener what punctuation marks are to the reader. He is not conscious of their presence, but he would be left floundering if they were absent. Some of the most effective parts of speeches are the pauses. They impart clearness to ideas, as well as aiding in emphasis and rhythm.