While both the speech and the presentation have the exact same layout – opening, development, and closing – they are two different formats, requiring two different types of delivery. More than likely, you will read a speech. A presentation, on the other hand, should never be read. It is spoken.
Speeches are much more formal and tend to be shorter than the presentation. The latter often includes visual aids which are not typically found with a speech. President Obama gives speeches; Zig Ziglar gives presentations.
If you are planning to toast the bride, deliver a eulogy, accept an award, introduce a speaker, or address a graduating class, you will be making a speech. If, on the other hand, you are a guest speaker at a convention, a conference, or a networking meeting, the chances are that you will deliver a presentation.
Speeches are easier to give than presentations because the words are in front of you. The secret to reading your speech, however, is not to sound like you are reading it; and, that practice. Lots and lots of practice. You need to be very comfortable with your words.
The presentation takes a lot of rehearsal as well but one of the big differences between the speech and presentation is that you are speaking around your main points and subtopics with the latter. The following is a simple example of an informative presentation:
A Opening
B Topic
1. Main Point
a. Subtopic
b. Subtopic
etc.
2. Main Point
a. Subtopic
etc.
3. Main Point
C Closing
By dividing your material into blocks of information, you will find it much easier to learn. I suggest using note cards, jotting down a word or a phrase for each main point, subtopic and subsequent sub-subtopics. Then practice speaking around those blocks of information. The same speech given to various groups of people will always have the same wording. On the other hand, the same presentation made to a number of groups will sound different each time you present it. The reason is because your wording will change according to how you feel at the time and the type of audience to whom you are addressing as well as their response to you.
Aside from the opening of both the speech and presentation, memorization is not a good idea. A memorized delivery sounds rote and artificial. I do suggest memorizing your opening, however. Being able to begin your delivery smoothly and without a mistake is a tremendous confidence booster.
No matter what format you are delivering, one of the secrets for success is knowing your material. Do not believe that you will do a good job without it.