Pragmatic rules help us coordinate the structure of the utterance with the context of the message.
To be an effective speaker (i.e., one who gets his message across without hurting himself or someone else), I must be aware of these three factors: Perlocution, Locution and Illocution.
Then I must apply the rules of discourse that will insure that they are correctly coordinated in my utterance.
The way we do this, by and large, is by coordinating the structure of the utterance with the context of the message.
This can be a cognitive quagmire! But children quickly begin to learn and apply these rules as soon as they begin to talk, if not earlier.
What are these rules? There are many but we will examine just a enough to get a flavor of what it is all about.
The first set involves coordinating the non linguistic (Expressive Graded) cues with the intent of the linguistic component of the message.