Are there syntactic constraints to code-switching? Based on Chan's University College London dissertation, this book argues that code-switched utterances are constrained by the same set of mechanisms that govern monolingual utterances. Building on the work of Mahootian (1993) and MacSwan (1997), Chan makes two additional claims. First, he argues that functional categories and lexical categories behave differently in code-switching. These differences lead him to distinguish between functional and lexical categories in the production process. Second, he extends his initial argument to claim that code-switching and pure languages are governed by the same set of constraints and principles not only for syntax but also for production and pragmatics.

After a brief introduction, the book begins with a critical review of the literature on syntactic constraints to code-switching. Chan concludes that the best approach is a null theory—that is, that there are no constraints that apply specifically to code-switching. Chapters 3 through 6 focus on the differences between functional categories and lexical categories in code-switching, with the first two of these chapters devoted to word order and the final two to c-selection and s-selection. The scope of these chapters is broad, and Chan offers examples from language pairs as diverse as French-Wolof and Tamil-English. In fact, given that Chan does not focus on Cantonese-English data until chapter 5, which is situated about half-way through the book, the title of the book is a bit misleading.

Chan claims that functional categories and lexical categories undergo different production processes and that this difference accounts for their different selection properties; for Chan, these production processes are the same in both monolinguals and bilinguals. Chapter 7 deals with the dual nature of prepositions in code-switching and the ways in which they behave like both a lexical category and a functional category.

Although many treatments of code-switching have been confined to syntactic processes, in chapter 8 Chan moves on to discuss the pragmatics of code-switching. He applies Sperber and Wilson's (1995) relevance theory and concludes that code-switching is motivated by the desire of speakers to optimize the relevance of their messages. This goal of optimizing relevance is true for both monolingual and bilingual speakers. Thus, as in his earlier discussion of syntax and production, Chan finds that a single theory can be used to explain both monolingual and code-switching utterances.

Due in part to the organization of the text, the main arguments of this book are very clear. The key points of the book as a whole are lucidly outlined in the first chapter, “Preliminaries” and in the ninth chapter “Conclusions.” Additionally, the author provides an introduction and summary of the chapters in the body of the book that serve to focus the readers' attention on the main points. The book is thus accessible to readers without a strong background in this area. SLA researchers interested in the three areas of code-switching discussed in this volume—syntax, production, and pragmatics—should find this book of interest.