This book is primarily concerned to give an account of how listeners behave as they participate in dialogues in which information is exchanged. What listeners have understood from what a previous speaker has said is frequently revealed in what listeners say themselves when they next take a turn at speaking. We shall examine what listeners say in their turn as speakers, looking for evidence of what they have understood previous speakers as saying. Detailed knowledge of such behaviour is fundamental to the development of our understanding of the cognitive basis of language use.

If we want to make claims about the nature of comprehension processes, we had better be sure that such claims will be widely applicable within the population. The subjects who participated in the dialogues illustrated here are drawn from a wide range of backgrounds and are diverse in their academic ability. They are drawn from Edinburgh schools and the University of Edinburgh, as well as from schools in the county of Essex and Essex University. They include young adults and adolescents of demonstrated intellectual ability, as well as 14-16 year-olds who are deemed by their schools to be in the bottom third of the academic ability range.

I am not concerned here to make quantitative claims. Rather, I draw attention to patterns of behaviour which occur repetitively in the data. The intention is to seek to explore the nature of the behaviour rather than to examine its detailed distribution.