Take a look at this conversation: John: The book isn't well written. Jack: Yes, the book is very well written. In some languages the second line will have a "No" at the beginning: No, the book is very well written. The difference is that in English "yes" means "I am making a positive statement", but in others "I agree with you". This leads often to misunderstanding when people speak English as a second language. Even advanced learners have a problem with shedding the way of thinking what yes and no means in their language, and this is rarely taught. Now the question: What is it like in your language? Is the meaning of yes/no like in English or the other way round?