Think of a speech as an inverted pyramid, with the topic being the widest section. From there, refine down into the purpose, followed by thesis, evidence, and arguments.
Speeches typically serve four general purposes: to inform, persuade, instruct, or entertain.
By taking a step back to examine the general purpose of the speech, a speaker reinforces his or her thoughts and ideas by making sure that everything presented to argue your case aligns to that general purpose. Anything that takes away from that purpose should be omitted from the speech.
Think of a speech as an inverted pyramid. The pyramid's widest point represents the most general purpose for the speech. As the speaker begins to refine the thesis and create supporting arguments, the pyramid gets narrower and narrower as he or she drives the point home. Many times, it is easy to focus on that narrowest point, but it is just as important to take a step back and consider the general purpose of the speech.
From a broad standpoint, the speaker should ask, "What do I hope to achieve with speech? Is the aim to inform? Persuade? A little of both, perhaps? Or maybe entertain? " There are four basic types (and thus, purposes) of speeches: to inform, persuade, instruct, or entertain. Each of these speech types may contain a little bit from the other types, in order to create a compelling package and ultimately, to get the speech to that narrowest point.
For example, imaging a basic topic, such as Facebook. Consider the audience: to whom will the speaker be speaking? What's their age and knowledge base? A crowd of college students might have a much wider knowledge base than say, a crowd of elderly audience members - but not necessarily! There are plenty of grandmothers who could run circles around a twenty-year-old on Facebook.
If the general purpose is to instruct, the speaker may conduct a demonstration on how to set up privacy settings on Facebook. As he or she further hones the purpose and thesis, the speech might trickle down into instruction about why it is important to specify one's privacy settings.
Now imagine a speaker who wants to persuade an audience - for example, an elderly crowd - to adopt a technology like Facebook. The speaker may have to do some instruction, but he or she will also want to talk about the social network benefits of Facebook or the cognitive benefits of lifelong learning and technology use. Again, this speech take a topic like Facebook and refines it down to a purpose, like persuasion. From there, the speaker can begin to craft a thesis, such as, "Facebook is a valuable tool for the elderly to remain connected to their loved ones while simultaneously boosting cognition and memory affected by aging. "
Whatever the purpose of the speech, before diving into the specifics of the thesis, the speaker must make sure to take a step back to examine the broad, general purpose of why he or she is speaking. The speaker will want to make sure that every piece of evidence and thought in the speech connects to that general purpose, in order to present a reinforced theme to the audience.
Source: Source: Boundless. "General Purpose." Boundless Communications Boundless, 3 Mar. 2017. Retrieved 29 Jun. 2017 from https://www.boundless.com/communications/textbooks/boundless-communications-textbook/choosing-a-topic-6/establishing-a-purpose-and-a-thesis-36/general-purpose-158-1828/
giving or consisting of only the most important aspects of something, ignoring minor details; indefinite
a result that is desired; an intention