Let me try on that one. This may be wrong, but I think when you are talking about language "pragmatics" refers to all that communication that goes on which would not show up in the written script of what was said -- facial expression, tone of voice, volume, etc.
Hi - Pragmatics is the branch of linguistics concerned with meaning in context, or the meanings of sentences in terms of the speaker's intentions in using them - so you would need to know the context to understand a particular text or utterance - for example:
Flying planes can be dangerous - this could have two meanings - 1. that planes in the air are dangerous or 2. that piloting a plane is dangerous - you would only know which is which if you knew the context
Jokes and newspapers make good use of this ambiguity