Pirates have a very distinctive flag and language.
The skull and crossbones. White bones on a black flag. Just about everyone around the world knows what these signs mean. If you see it, you know that pirates are nearby. And when you think of pirates, there is an immediate sense of danger, as you know what you are about to face. The reputation was so strong and the flag so distinctive, that when a pirate vessel raised their flag, ships would often surrender immediately because they knew what would happen if they didn't.
Many readers will know the significance of September 19th. This has become recognized internationally as "Talk Like A Pirate" Day. It's a bit of a silly holiday, but everyone is supposed to talk in their best pirate lingo. Because of the distinctiveness of the stereotypical piratical language ("arr", "ahoy", "matey", "shiver me timbers" and so on), everyone knows what they need to do to "talk like a pirate". If you walked up to anyone in America and said "Arrh, me hearties, where be the wenches?", people would likely immediately recognize you as trying to speak pirate.
As Christians, we should be just as obvious. The Bible even talks about it, saying that we can be told by our love and spirit. There is a certain attitude that we should have that will tell people "Hey, there's a Christian!" If we saw a flag with Big Bird's face on a pink background, we might be surprised to find it flying on a pirate ship. In a similar way, we need to be careful what kind of flag we're flying. Are we showing a distinctive flag that will let people know who we are and who we stand for? There should be no mistaking us for others in the world, regardless of how we're dressed.
Our speech and language should also mark us as followers of Jesus Christ just as surely as a pirate's odd meter and verbiage makes them identifiable. If we use foul language and tell off-color jokes, what will people think that we are? Will they be able to tell that we love and worship Jesus? How do the things you say in your day let people know that you are a Christian. The Bible talks about a tree producing good or bad fruit. Well, we're going to produce some kind of fruit whether we want to or not. Can someone look at our fruit and tell that we love God and follow Jesus?
If not, then maybe we're flying the wrong flag.
Make a tree good and its fruit will be good, or make a tree bad and its fruit will be bad, for a tree is recognized by its fruit.