An impromptu speech is given with little or no preparation, yet almost always with some advance knowledge on the topic. When called to speak "off the cuff" on the "spur of the moment," is is usually because the speaker is quite knowledgeable about the subject. For example, if called on to speak in class, a student might give a short impromptu speech about a topic that was in the assigned readings. Business meetings also use a "check in" to tell everyone else about a current project. In small informal meetings, the audience will interrupt an impromptu speech and ask questions, which helps guide the speech and the information that is presented. When campaigning, politicians sometimes respond to reporters or voters almost anywhere and at any time.
Remember that you are generally in control of the content you are presenting, so you can include topics that you want to talk about. Additionally, you can use personal examples from experience to support what you are saying. Since you are an authority on the topic, you want to speak with conviction like you really mean it. Your delivery will naturally be more conversational and spontaneous. Since you are not prepared with pages of notes, you are more likely to speak directly to the audience just like if you were speaking to another person in a conversation.
Since you are not well-prepared, you may have difficulty thinking of what to say or formulating the ideas once you get up to speak. Although you are familiar with the topic, your speech may lack details and supporting information. If the audience is passive and does not ask questions to guide you, you may overlook some significant content. Hopefully, someone in the audience will ask questions so you can fill in gaps. Additionally, impromptu speaking is rarely appropriate for occasions which require more reasoned discourse with supporting ideas or more formal events.
Tips for the Speaker (Impromptu Preparation)
What do you do if you are asked to speak at the last minute? It is best to become familiar with common organization patterns so you can apply them in any situation and then also consider what you have been asked to speak about. Are you presenting your opinion? State your opinion, the reasons why you support that opinion, and conclude. Is it something that happened? Retell the event from beginning to end (first, next, then, etc.). Is it a demonstration? Explain each step in the process from first to last.
Make sure to plan an introduction and a conclusion. If possible, take a few moments to think about what you want to say to introduce the topic and have some way of concluding.
Make a few notes for yourself on a card, phone, or iPad. Or, text yourself a few single words to remind yourself of the important ideas.
Consider the simple three part outline of an Introduction, Body, and Conclusion, and fit your ideas into that pattern.
Do not try to remember a detailed outline for your entire speech; just remember the order of important points.
Be sure to stop when you have made your points.
If you do not know what to say next, you can summarize and paraphrase what you have just said, and then will probably be ready to move on to the next topic.
Remember that, in most situations, you will know more about the subject than the audience. Usually you will not be called up to speak impromptu about something you know nothing about, so you have probably spoken about the general topic before or you probably have knowledge to share with others.
Talk like you mean it. In other words speak with conviction. You are explaining your ideas or knowledge and you are an authority.