What are the three principles of public speaking, and how do you evaluate a speech based on these principles?

What will be an ideal response?

A good standard to use in evaluating a classroom speech involves how well it conforms to the principles of public speaking. You evaluate a speech positively when it follows the principles of public speaking established by the critics, theorists, and practitioners of public speaking. You evaluate it negatively to the degree that it deviates from these principles. The three principles of public speaking are as follows: 1) Speaking on a subject that is worthwhile, relevant, and interesting to listeners. 2) Designing a speech for a specific audience. 3) Constructing a speech that is based on sound research.