This volume represents the first attempt to assemble studies of the effects of the second language (L2) on the first (L1). Underlying the design of the book is Cook's (1991) notion of multicompetence, which refers to knowledge of two or more languages in one mind. From various perspectives and to varying depths, the authors bring evidence to bear on the conceptualization that the L1 of an L2 user is not encapsulated but susceptible to the L2 influence.

The book contains 13 chapters: In chapter 1, Cook opens with a rationale for researching the L2 effects on the L1, drawing on Weinreich's (1953, p. 1) view on interference as “those instances of deviation from the norms of either [italics added] language which occur in the speech of bilinguals as a result of their familiarity with more than one language.” He then goes on to introduce his notion of multicompetence, arguing on the basis of (a) the rights, (b) the number, and (c) the distinctive characteristics of L2 users. He discusses several models of the relationship of the L1 and L2 in the mind of an L2 user, such as the separation model, the integration model, and the interconnection models, suggesting that, together, they make up an integration continuum. Cook closes the chapter with an appraisal of the methodologies employed by the authors of the subsequent chapters.

The ensuing nine chapters, contributed by Laufer; Pavlenko; Cenoz; Jarvis; Porte; Dewaele and Pavlenko; Murphy and Pine; Balcom; and Cook, Iarossi, Stellakis, and Tokumaru report on empirical studies of changes occurring in the L2 users' L1s in domains such as the lexicon, semantics, syntax, and so forth. The remaining three chapters are written by Satterfield, Jessner, and Kecskes and Papp, who, respectively, present a reanalysis of the data from previous research, a new way of looking at multilingualism, and indexes of the L2 to L1 influence for measurement purposes.

With such an array of studies, this book opens up a new genre of research that is, in part, purported to challenge some fundamental SLA conceptions—for example, the monolingual native speaker (NS) model on which SLA research to date has been based. The studies collected in this volume have jointly revealed two phenomena about L2 users—namely, (a) that an L2 user's L1 is different from that of a monolingual NS, and (b) that an L2 user has an expanded linguistic and conceptual repertoire as a result of knowing more than one language. If such findings can be further confirmed by a significant amount of systematic research, theoretical and empirical, SLA research will ultimately have to forsake the monolingual NS model. Until then, however, it seems that researchers in this area will have many difficult questions to settle. For example, to what extent is an L2 user's L1 competence different from that of a monolingual NS? What are the extent and depth of changes taking place in the L1s within and across L2 users? Answers to questions of this kind may shed light on the robustness of the notion of multicompetence. Clearly, to this end, the current research has yet a long way to go.

This book is largely descriptive and comparative in nature, and as such, it provides a rather flimsy understanding of why the L1s of the L2 users change the way they do. In spite of Cook's admonition about the comparative fallacy (Bley-Vroman, 1983), a notable number of empirical studies reported herein nevertheless compare the L1s of the L2 users with those of the monolingual NSs, labeling resultant differences as “deviance,” “contamination,” and so forth. Moreover, the overall tendency is quite strong toward attributing any differences exclusively to the L2 influence, and this is, in some sense, reminiscent of the earliest approach to SLA, the contrastive analysis hypothesis (Lado, 1957), which the new genre of research has rebuked for its inadequacy. What thus seems to be happening is that the comparative fallacy is taking on a different guise. Changing the direction of comparison, which appears to be what the current research on the L2 influence does, will likewise blur the uniqueness of L2 users and learners, leading potentially to a biased understanding of the L2 users' competence.

Although issues remain, this book nevertheless broaches a long-overdue discussion in SLA research on the role of the NS in achieving an understanding of L2 users and learners. Needless to say, it deserves and demands serious attention from anyone interested in SLA.