Energy is the basis of all things. But not all things are created equal - not all things demand the same amount of energy to happen. And, to drive this point further, the same things do not demand the same amount of energy to happen for all people. Some people can do certain things with a lack of effort, while others have to struggle their hearts out in order to make that very same thing happen.
Energy is not a universal currency, as it were.
This applies very much to communication. Some people can communicate rather effortlessly, going on and on and on in a state of constant chattering about this and that. Others have to make the effortial equivalent of climbing a hill to say just the one thing. Not to mention two things.
Communication is not a universal constant, as it were.
This is important to keep in mind, as you will run into people who have to effort to communicate. You will run into them at a regular basis, and you will most likely misunderstand their energy requirements for something else. In benign cases, you'll take it for a certain ponderousness, a tendency to think that one extra second before speaking. In other cases, you'll take it for rudeness slowness (with a negative connotation). Or something else, for better or worse.
It's not what they're saying. It's how much they have to effort in order to say it.
As it were.