The Intent or aim of a speaker making an utterance; What you're trying to do by how you say something.
Example: How many different ways can you use the word 'okay?'
You choose how you say that word depending on what you want it to do for you.
Do you want to signal that you think someone is kinda crazy? You go, "Y'...okay..."
Or if you want to signal that you are pleased by what you've just been told, you say, "Okay, cool!"
If you are about to give an order but you want to make it sound like you are just figuring things out yourself, you say, "Okay. Here's what to do."
Every time we talk we are doing something and trying to make something happen.