This a tutorial lecture describe on Speech; major focus on Selecting a Topic and Purpose. A single infinitive phrase that states precisely what a speaker hopes to accomplish in his or her speech. One of the most common stumbling blocks for novice public speakers is selecting their first speech topic. Generally, your public speaking instructor will provide you with some fairly specific parameters to make this a little easier. You may be assigned to tell about an event that has shaped your life or to demonstrate how to do something.