This book provides a new way of studying grammar. The basic thrust of the book is to investigate grammar based on a prosodic unit, the intonation unit (IU), in spontaneous speech. The author challenges the dominant practice in the study of syntax, which has been to focus on the unit of the artificially constructed sentence. The book shows that some basic notions developed from sentence-level data often do not account well for speech data. For example, in many versions of syntactic theory, the basic syntactic structure of any sentence is assumed to comprise both an NP and a VP (with variations in terminology). However the author shows that a Mandarin sentence in spoken discourse can consist of a lone NP or a transitive verbal expression without any explicit argument (which is not due to anaphora).