There are four kinds of purposes of speaking. They are informative speaking, invitational speaking, dis-positional speaking, and actuation speaking. This is the explanation of four speaking purposes above:
Informative Speaking: Informative speaking seeks to inform. Its goal is that the listeners understand something in the same way that the speaker understands that subject. The speaker is sharing meaning and ways of understanding. Informative speaking uses facts, data, logic, evidence, and other solid information and structured presentation to help the listeners understand and remember the information presented.
Invitational Speaking: Invitational speaking is often similar to informative speaking, but adds judgment into the mix. The invitational element is hence an invitation to listeners in agreement or evaluation of some sort. This evaluation may be of an idea, another person, an event, and an object of some kind, an event or anything else that which judgment may be applied. Invitation speaking uses evaluative and judgmental language and rational logic to present the case. As with informative speaking, it may well appear cool and factual and use classical argument principles. Invitational speaking is more difficult that informational speaking as the students are asking to the listeners to accept particular evaluation criteria and processes of assessment with which they may not agree. Academics perform invitational speaking when they criticize others’ research.
Dis-positional Speaking: Dis-positional speaking is more persuasive in inert that invitational speaking in that it seeks to gain agreement on an attitude, value or belief. Whilst academic speakers should not really use dis positional speaking, it can be argued that everything is a belief and that there are unquestioned cannons and paradigms that many academics accept without question, and to challenge these can be particularly perilous.
Actuation Speaking: Actuation speaking seeks to get people to act, to perform in some way. In practice this can be easy for simple actions and hardest of all for actions that the person may not normally undertake. In this way, actuation speaking can be considered to be ultimate in persuasive speaking. In its more difficult form, actuation may well be preceded by other forms of speaking, as you may need people to understand, agree with a judgment and even change what they believe before they will take the actions you propose.