Bill Gates making a speech
Those who deliver speeches often know the importance of a strong conclusion.
The role of a conclusion in a speech is to signal to the audience that the speech is coming to a close and help them remember the most important points from the speech.
While this may sound unimportant or superfluous, if you do end your speech without indicating you are about to do so it can feel extremely abrupt and confusing to the audience. Make sure to give the audience closure with your ending.
It is important that you always tie your conclusion back to your introduction. This can most effectively be done by circling back to your "hook," or attention grabber. The same 'vehicle' or theme, for example, an anecdote about Margaret Thatcher, is employed to conclude the speech as was used initially to introduce it. A clever closing line is common place and many strong speakers will simultaneously reference the theme discussed in the introduction and conclusion.
The end of your speech is going to form your audience's lasting impression of everything you've said. This is why your conclusion is the perfect opportunity to secure the key elements of your speech in your audience's mind. Make sure that you reiterate the thesis statement from your introduction, highlight the most important points from your speech, and then relate the concepts of the speech back to reality so your audience can see how it is applicable to their world.
By reiterating your introduction you bring the audience's mind back to the overall purpose and message of your speech. By signally the end of your speech your ensure that your audience leaves with an overall positive impression of your speaking and does not feel confused. By highlighting the main points, you ensure they are fresh in your audience's memory.
Think of your conclusion as an opportunity to summarize. While your speech is undoubtedly well organized, concise, and poignant it is still possible for listeners' attentions to wander or for them to not fully understand a certain section of your speech. Your conclusion is the perfect place to reconcile any miscommunication with your audience.