Way back when I taught speech, I used the following illustration every semester:  

A plumber wrote to the National Bureau of Standards saying he had found that hydrochloric acid opens plugged pipes quickly and asking whether or not it was a good thing to use. A scientist at the bureau came back with this reply:

“The uncertain reactive processes of hydrochloric acid place pipe in jeopardy when alkalinity is involved. The efficacy of this solution is indisputable, but the corrosive residue is incompatible with metallic permanence.”

In a return letter the plumber thanked the Bureau and said he was happy to learn that his method was right. The scientist, of course was worried about he misunderstanding, so he showed the letter to his boss, who wrote the plumber:

“Hydrochloric acid generates a toxic and noxious residue which will produce submuriate invalidating reactions. Consequently, some alternative procedure is preferable.

Immediately the plumber wrote back again, agreeing that “Hydrochloric acid works just fine.” Since that threw the two scientists into complete confusion, they took the problem to their top boss.

After a few minutes’ thought, he penned this letter to the plumber:

“Don’t use hydrochloric acid. It eats the dickens out of the pipes.”

This is a good example, a key motto, of public speaking:

Clarity, Simplicity, Brevity

Speaking is different from writing. When you write something, your reader, if he misses something, can go back and search, take time to research what you asserted and confirm what you are saying is correct.

When you are speaking, you have one chance to gain your audience’s attention, and more important, their trust, and keep them with you as you communicate what you have prepared.

Be clear: No matter what the occasion, do your homework before you speak. Use well-prepared, well-organized content. “If you can’t explain it simply, you don’t understand it well enough.” Albert Einstein

Be simple: Employ language familiar and accessible to your listener. “Simplicity is the loveliest garment truth can wear.”

Be brief: Stay within prescribed time limits. “The mind can only absorb what the seat can endure.”  

Respect your audience.

Once you stand up in front of a group of listeners, you have placed yourself in the position of being their servant. You are taking up their time. You are transmitting words which will fill their minds, and influence them (hopefully) for good.

They are giving you an hour of their lives. You  have no right to waste it.

You have no idea what happened in their lives before you intersected with them. The words you speak may be life-changing. They may take away a principle which will impact them the rest of their lives. Or you may distract them for a few moments from whatever is troubling them, lift them up, inspire them.  

Do not waste your time or theirs by being ill-prepared, using “filler” or sharing personal experiences for the joy of hearing yourself talk about yourself…unless your story will truly make a difference in their lives.

Focus on your message.   

Public speaking should always focus on the message, not the messenger. Don’t get in the way of the message by distracting your audience with your appearance and delivery.

Do not draw undue attention to yourself. You are a channel. A conduit. A vessel.

Dress appropriately. Today “casual” is the accepted form of attire for most occasions. Nevertheless, you should still be at some level of “pressed and dressed.”

Check your posture.  Stand up straight. Keep both feet on the floor. Weight evenly distributed. Do not slouch or lean.

Omit nervous habits. Be aware of nervous gestures or repetitive speech patterns. Listen to yourself. See yourself from the audience’s point of view. These days it is easier than ever to record yourself and assess your own performance.  

Look them in the eye.  The old trick of “looking above their heads” is not an acceptable tactic. Look your audience in the eye. No matter how large the crowd, divide your audience into three or four groups and look at one person in that section—the friendliest face. The people in that group will feel as if you are looking at them.

Speak to be heard and understood.  Adjust to the situation. Speak loudly enough to be heard. Do not require your audience to adjust to you. You adjust to them. If you see them leaning in to hear better, speak up. If you see them looking puzzled, go back and repeat.  

My verse for teaching: “The servant of the Lord must not strive, but be gentle unto all men, apt to teach, patient…” II Timothy 2: 24

When you speak, remember: you are there to serve.