There 4 ways to give your speech in public speaking. Here are the next 2 ways to deliver your speech in public speaking.
Impromptu Speech
In an impromptu speech the speaker has not prepared a speech and is delivering his thoughts and word on the spur of the moment. This method is very flexible but rarely achieves the quality of a well prepared speech. It is best avoided if you can. But if you think you may be called on to say a few words it is handy to have a few "lines" prepared to avoid any embarrassments.
Prepare a speaking outline and memorize the ideas
This approach is known as the extemporaneous method. The speech can be delivered with or without notes. When thoroughly prepared (which can include writing your speech in full initially) and practiced there is little need for notes.