That is an interesting question. While I often use those two words interchangeably, there is a difference. I liken pacing to your overall speed. Do you generally speak slowly, quickly or at a moderate rate of speed? In North America, a good pacing is moderate. If you speak too fast, you will tire your listeners; if you speak too slowly, you will put them to sleep.

Speed, within the context of your pacing, refers to changes you make with a phrase, a sentence or even a paragraph. Changing your speed as you talk makes for an interesting delivery. If your speed is consistent throughout, then your delivery becomes static or even hypnotic.

When you are in normal conversation, you change your speed according to many variables as you describe something that is in the past, in the present or in the future. Whether you are discussing a movie your saw, a book you plan to read, an email you received, the weather, your family, your company's budget or a contract you sold, your conversational speed varies accordingly. The same 'rules' apply to public speaking.

Were I to say the following sentence to someone, there is a good possibility that I would speed up on the last part of the sentence - those words that are in bold.

    The deer looked up, froze for a second, and then bounded away in a flash.

Try the above example, increasing your speed on those last 5 words. This is certainly not the only way to say the sentence however. It is just one of many ways. There are no absolutes in speaking when it comes to color: color refers to the life, the animation and the emotion you allow to be seen and heard when talking, be it on the podium, at the head of the boardroom table, or even in conversation.

As you speak throughout your day, concentrate on your speed, paying particular attention to the times when you speed up or slow down. If you were to tell your children to Stop It!, in all likelihood, you would say it very quickly. If, on the other hand, you were to pay someone a compliment, What a great job you did!, it is possible that you might say those words more slowly, emphasizing the word great, for example.

Good expression, whether in conversation or for public speaking, deals not only with variety in your expression and the tone of your voice, but also your speed. Change it up once in a while. It will make for a much more interesting delivery.

Author's Bio: 

The Voice Lady Nancy Daniels offers private, corporate and group workshops in voice and presentation skills as well as Voicing It!, the only video training program on voice improvement. Check out Nancy’s Voice Training and discover the best means of adding some life to your voice and your delivery.