The discussions in this book assume the reader has more than a conversational knowledge of ANSI C programming. This book is not a tutorial on the entire language. It is aimed at the advanced beginner to intermediate-level programmer who feels relatively comfortable writing C programs but who has a distance to travel when it comes to the topic of pointers.
What exactly do you think that means? I particularly don't understand how the word conversational is used here. Conversational usually refers to something that has to do with verbal conversation.