About shared understanding

"Most of the time, we realize, we do not fully understand what another person says. Indeed, in practice, shared understandings occur only occasionally, if they occur at all. And when they do, it is people testing and checking each other's talk, by them questioning and challenging it, reformulating and elaborating it, and so on." John Shotter, 1993, in his book  Conversational realities: Constructing life through language.