The really great thing about jargon is that it saves time. Generally, jargon shows up as a way of expressing some relatively complex, recurring thought or statement into a single word or short phrase. In order to be jargon and not just new vocabulary, this has to happen in a somewhat specialized context. If I coined a new word to talk about some aspect of grocery shopping it wouldn't be called jargon; it would just be a new word since everyone goes grocery shopping. On the other hand, if I came up with a term for some arcane literary process, and it managed to catch on in the field of literary critisizm, then that would be a bit of jargon. This is why jargon can be so great. Instead of having to give this long, technical definition or proposition, I can use this one piece of jargon and everyone who is familiar with the concept will immediately know what I am talking about.
Everyone who is familiar with the concept.
And herein lies the problem. Too often, we use jargon when our audience is not at all familiar with the concepts it represents. So instead of helping communicate the jargon is a hindrance. This downside is obvious and we see it all the time. Teachers and professors do it, and Christians are terrible about it; but really anyone with any technical expertise can get us with it. Contractors and car people do it all the time too. Of course, depending on the audience's pride, they are generally not going to ask for an explanation because they are embarrassed for not knowing the terms before hand. (Any of you guys out there ever nod sagely when your mechanic tells you that the pifflethwattle is shot and if you don't bananafringe your tintbannder the whole gutrude may have to be replaced?).
And that leads to the second danger of jargon: jargon can be used to deliberately obfuscate something. I generally suspect that mechanics do this to me counting on my pride to let them charge me for stuff I don't know anything about. But maybe I am just to suspicious. Either way, jargon can certainly be used as a tool to gain an edge of power over a situation or another person.
But what strikes me as the most dangerous effect of jargon is the way it can obfuscate meaning to the person who uses it without their ever realizing that they have no idea what they are talking about. If I have any expertise it is in two areas: Christianity and Philosophy. In both of these areas I am forever catching others and myself using terms that we ourselves aren't entirely clear on. Generally these will be terms that we have heard often enough that we understand how they ought to be used but which we have never really investigated. Think about it; do you know what it means to say "I claim the blood of Christ" or "this is a question in Meta-ethics which is linked to the concept of goodness qua positive being"? You tintinnabar needs some real bananfringing.
I think that this is the worst way that jargon can go bad because it allows for self-delusion. If you are accidentally using language you audience doesn't understand, it is unfortunate but correctable. If you are deliberately obfuscating something, that is a problem but at least you know what you are doing. But when jargon goes wrong in this third way, you might say something completely accurate without having the least idea what the truth is. Students who do this, get A's on tests without being educated and tragically don't even know that they are ignorant. Philosophers who do it miss out on the wisdom they are seeking and, because they used the jargon correctly, they don't know where they went wrong. Christians who do it are probably in the worst shape. They have no idea what they are talking about but they think that their phrase is their answer.
Let me challenge you to try something I do every so often. Stop using jargon for a while, try a week. Don't use any word unless you actually know what it means and are pretty sure that a middle school student could understand it. Don't ask God for "grace and peace" ask Him for what you want. Find out whether or not you know what you are talking about when you claim that "sanctification is a work of faith". Do you think you could explain the egocentric dilemma to a ten year old? Let me know how it goes.