There is something to be said for irreverence. It is politically incorrect, it cuts through the ether of "sensitivity," and it often results in clarity being brought to an issue. Front and center for this discussion is Mark Driscoll, who is both loved and hated in the Reformed world. There are many for whom his style is simply too crude or crass. Others, such as myself, find his use of language and humor refreshing and culturally engaging.
But the larger issue here is the idea of irreverence in our speech. I am not here, going to defend crudeness, filthy speech, dirty jokes, or coarse profanity. What I am referring to, here, is a way of speech which is humorous but not profane; satirical but not cruel. This is a way of speaking which reflects the culture of the day without compromising one's integrity or the clarity of one's message.
In one of the first speeches I heard Driscoll give, he defended using the culture's language and interests when communicating the Gospel. He offered examples from Scripture (such as having Titus circumcised for the sake of the people he was going to minister to, because they believed circumcision was important) of Christians adapting to the culture. Essentially, what Driscoll did was point out that contextualization is a biblical notion. Now, I would say that the way in which Driscoll speaks (both during his sermons and in his books) is a contemporary example of contextualizing language to fit the culture being reached out to. In Driscoll's case, this is Seattle, WA; a place filled with indie rock, irony, and Starbucks at every turn. He speaks the everyday language of the people who come into his church and read his books. For example, instead of saying that Mary was accused of sexual impropriety, he says that everyone thought she probably was knocking boots in the backseat of a car at prom. This manner of speaking engages the ears of his audience, he engages their sense of humor (which few would deny is important in communication), he communicates in a way which shows that suspicion of lurid sexual behavior between the time of Mary and our time is really not that different, and he speaks in a way which connects with the other six days of the week for his listeners.
Essentially, church people have a way of speaking which makes sense within the confines of Sunday morning or seminary classes, but which doesn't really reflect their way of speaking for the rest of the week, because they are going into a world which does not speak that language. Many communicators have been taught that they should be ultra-conservative, trying not to offend others with their words. Now, this is often true. But if we were so cautious as to never offend anyone, we would often not be able to say anything. And we certainly couldn't say anything true.
Have I been clear enough? As Christians, we should be loving in our words, we should speak in a normal way that our listeners will understand, and we should contextualize to our listeners. If we believe that communicating effectively is important, then I would suggest we do what Driscoll (in this example) has done, and sometimes that involves ruffling the feathers of the more conservative listeners for the sake of effectively reaching those who are not from that same background.
Again, I would say that Driscoll has not crossed any moral lines with what he has said, and any examples should be taken on an individual basis, one at a time. I don't think there are any examples of Driscoll speaking in an unloving or biblically impermissible way.
Excuse me now, folks. Let me make it even plainer. Though Driscoll's way of speaking is very different from the way your average pastor speaks from the pulpit, it is not Biblically forbidden. As such, it is a matter indifferent and a question of Christian liberty. This means that if you don't like the way that he speaks, you should go pick up your collection of Spurgeon or Edwards and stay away from Mars Hill Church; though I actually recommend that you get a sense of humor, instead, and lighten up.