THE STUDY OF LANGUAGE is a basic linguistics introductory published by Cambridge University Press. Generally CUP's linguistics textbooks are the best in the field, so I acquired this book to see how its basic introduction was. Unfortunately, I was left very disappointed, and doubt that this is a trustworthy introduction to the field.
The first warning sign is that there is no biography of the author George Yule, and therefore the reader cannot see how he is qualified to prepare a textbook, where his graduate degrees are from, etc. The author then goes on to pepper his work with urban legends, such as the assertion that English spelling comes from Dutch printers, and the tired yarn that William James had a run-in with a crazy old lady who believed the world was on the back of a turtle.
However, the greatest mark against the book comes in its use of Bill Bryson as a source. Bryson produced two popular-linguistics books over ten years over, even though he had no training in linguistics. Many linguists have condemned the books for their abundance of urban legends, misunderstandings, and total lack of error-checking ("Eskimo's have 50 words for snow", "Russian has no word for "engagement ring" or "fun"). In THE STUDY OF LANGUAGE, Yule uses questionable passages from Bryson's books to illustrate points, and even seems to recommend them to students.
Concerning other aspects of the book, it does not seem usable. Yule spends very little time on phonetics and phonology, and introduces only concepts found in English, even though most students undoubtedly wish to know about more exotic languages. The insubstantial offerings on phonetics and phonology make this book entirely unsuitable for students of philology; how can you teach the comparative IE philologists of tomorrow if you don't even mention laryngeals? Yule also has an annoying tendency to speak to the reader as if he was a child. While this is an undergraduate textbook, it is written at the reading level of a high school work. The epigraphs of each chapter are amusing, but any writer who quotes "Beavis and Butthead" is certainly not teaching at an intellectual level.
In summary, I recommend against the use of THE STUDY OF LANGUAGE as a textbook. The book is clearly not trustworthy, and does not seem an effective and rigorous introduction to linguistics. I feel it would be better to teach from Cambridge University Press' individual introductions, such as Laver's PRINCIPLES OF PHONETICS, Lass' PHONOLOGY, etc.