Let your speech always be with grace, seasoned, as it were, with salt, so that you may know how you should respond to each person. (Col 4:6)No, that is not a command to "spice up" your language with some swearing. The type of "salt" is specified: "grace". But just what does that mean? Are we to "say grace" before a meal? Clearly that doesn't make sense (except, perhaps, since we're talking about "salt", it is mealtime in view ... no, that can't be it.) Some think it means "saved by grace" grace. That is, "We should always be speaking the Gospel." That hardly seems right, either. So we are to always speak with grace. What does that mean?
I think Paul helps us elsewhere.
Let no unwholesome word proceed from your mouth, but only such a word as is good for edification according to the need of the moment, so that it will give grace to those who hear. (Eph 4:29)He speaks of giving "grace to those who hear." I think that's what he had in mind in the Colossians verse, too. And he's more descriptive here. No "unwholesome word". Words "good for edification", paying attention to "the need of the moment". This kind of speech is other-centered. It eliminates the "unwholesome", which can be translated "corrupt", "rotten", or even "worthless". It substitutes only speech that edifies.
So that is "salty" speech. We only say nice things!
That would be a misunderstanding. Sometimes to edify you need to remove rubble. Sometimes, like salt in an open wound, words may hurt. It isn't always "nice things" -- pleasant to hear -- but it should always be beneficial, whether or not it is pleasant.
Now, we can complain about the way "those guys" talk about us. They can be mean-spirited, cruel, bullying words. I don't know why believers would expect something else from unbelievers. This command, on the other hand, is to believers. It is our requirement to speak with grace, to edify, to build up. It is our command to know what is required for each person ("the need of the moment"). It is our instruction to season our speech rather than tear down. So, how are we doing there? Do we return verbal slap for verbal slap? Or do we turn our verbal cheek and speak with grace to edify? Jesus was known for His gracious words (Luke 4:22). Shouldn't we, His followers, be known for the same?
1 The term comes from the way that sailors ("salt" is slang for a sailor) speak, as in "swears like a sailor".