When you use the method of delivery, you become so familiar with the substance of your speech that you need only a few brief notes to jog your memory?

When you use the extemporaneous method of delivery, you become so familiar with the substance of your speech that you need only a few brief notes to jog your memory.
Extemporaneous method is a method in which you spoke without special preparation. In this method, jog your memory and then you are on, you can say whatever comes in your mind, it looks natural, you can take examples from your life. some people like this method and some people don't.