As with many common verbs, the meaning of “to say” in the Bible is highly dependent on context. Who is speaking? Who is hearing? What is it about? Is it a command, a message, an apology, instruction? All these things enter into the meaning of “say.”
In general, though, “saying” has to do with sharing truth at various levels – from the most exalted power people can have to perceive the Lord’s desires directly to the most basic of orders issued to people at their lowest.