I always buy this book for new parents because it contains a wealth of fascinating material about learning to talk. The author, David Crystal, is a professor of linguistics with a special talent for simplifying technical information and making it interesting and relevant to the layperson. As a former student of linguistics myself, I can assure you that he manages to do this without sacrificing accuracy.
As the title suggests, the emphasis is on observing your child's language. The book explains what developments to expect at each stage from birth to the early school years. It also gives practical exercises you can do with your child to discover what pronunciation, vocabulary, and grammar he or she has learned. These exercises are simple, often using the child's toys, and are designed in such a way that the child will not feel that he or she is being tested.
I believe that even the most observant of parents will find something in this book that they would otherwise have missed. For example, did you know that 3- or 4-year-olds tend to assume that things happen in the order in which they are said in a sentence and that this can result in misunderstandings? The author gives the following sentence as an example: 'Now, before you go out to play, I want you to put all your things away!' A child will pay attention to the order of the words 'go out to play ... put all your things away' and will go out to play first! As the author explains, it's all to do with subordinate clauses, and children do not fully master these until later.
This book also provides reassurance that what looks like a problem can actually be a sign of progress. For example, children go through a stage of producing incorrect past tense forms, such as 'goed' and 'knowed'. David Crystal explains that this happens because the child is not simply imitating adult speech. Rather, it has started noticing patterns in speech and is working out the rules for itself. Having noticed pairs such as 'walk'/'walked' and 'jump'/'jumped', the child devises a rule that says to add 'ed' to a verb to form the past tense. Later, the child will notice that there are exceptions to this rule and will correctly produce 'went' and 'knew'.
My only criticism of this book is that it has no index. Apart from that, it's excellent.
