Observe three different speaking situation.

Public speaking differs from written communication in that the audience is present, gathered for some occasion.

The three main types of group speaking situations may be described as :

The informative speech - conveys information,

the persuasive speech - is a call to action,

the special occasion speech is given to commemorate a person or event.

Good public speaking always accounts for these three components :

The audience is present, gathered for some occasion.

The occasion has norms and expectations that a speaker must recognize.

The speaker has some purpose, something they are trying to accomplish or set in motion.

Good public speaking always does one of these three things :

Informs or Instructs the audience on newsworthy events or situations.

Teaches a lesson on any number of given subjects.

Entertains with humor, satire, fiction and nonsense.