So academics go on using material that is sometimes an object of practitioners' scorn, because of this other inevitable gap-again, a gap which is not only in time (new practices take time to diffuse, to become widespread enough to 'alter the general picture' perceptibly), but also in comprehension (practitioners tend to speak to one another in special languages, understanding much that is not said, sharing a common experience that is the real basis of communication);it needs a person with a foot in both camps to make what is happening accessible to outsiders