The thesis advocated by Wexler in this book challenges traditional views of the makeup and genesis of Yiddish and Modern Hebrew. Traditional views assumed that “Yiddish was either a ‘deformation’ or a ‘creative Jewish outgrowth’ of High German, with attrition of Germanisms and acquisition of Slavicisms resulting from prolonged contact with the Slavic languages, while all historical attestations of Hebrew were regarded blindly as instantiations of Classical Semitic Hebrew” (3). Wexler's counter-proposal is twofold: On the one hand, Yiddish is Upper Sorbian relexified (in the 12th century) on the basis of High German phonetic strings, and Kiev-Polessian relexified on the basis of Yiddish and German (15th century); in this view, Yiddish is typologically a Slavic language with a German lexicon. On the other hand, Modern Hebrew is Yiddish relexified on the basis of Classical Hebrew phonetic strings; in this view, Modern Hebrew is typologically Slavic, like Yiddish, with a Classical Hebrew lexicon; hence, it is not genetically related to Old Semitic Hebrew. The aim of the book is to document this twofold proposal.

The methodology designed to document the hypothesis consists in a comparison of the languages involved. For example, the properties of Yiddish suffixes of German origin match those of Slavic suffixes rather than those of German; Yiddish lacks overt affixes that the Slavic languages lack, while German requires overt affixes in the same contexts; likewise, the properties of the two diminutive affixes of Yiddish pattern with the Slavic languages rather than with German. A long list of constructions where Yiddish pairs with Slavic languages rather than with German is provided (18) and detailed data are presented in chap. 4.

The book contains an introduction and five chapters, an impressive bibliography of some 80 pages, and name, example, and subject indexes. It is organized in the following way. Chap. 1 starts with a full statement of the relexification hypothesis as it applies in the case of Yiddish; it then provides a definition of the process of relexification, a discussion of 17 tests designed to detect cases of relexification, a discussion of the social motivation for creating a language through this process, and some thoughts on why some people (scholars or not) might not be sympathetic to the idea that relexification may play a role in language genesis. This chapter also contains an overview of the features that support the relexification hypothesis in the case of Yiddish, some historical facts about the populations involved, and a history of the research underlying the proposals advocated in the book. Chap. 2 summarizes the various traditional approaches to the study of Yiddish and other Jewish languages (e.g., Weinreich, Mieses, Katz). Wexler's conclusion is that these approaches cannot account for the complexity of the facts. Chap. 3 is basically an introduction to the relexification account of Yiddish and Modern Hebrew, with further discussion of the traditional views. It contains a detailed description of the source and composition of the Yiddish lexicon, such as cases of conflation, synonymy, and loan words, and it provides guidelines for constructing an etymological dictionary of a relexified lexicon.

Chap. 4, the most important of the book in terms of length, provides data documenting the two-tiered relexification hypothesis for Yiddish: from Upper Sorbian to German, and from Kiev-Polessian to Yiddish and German. The chapter begins with a summary of the findings. These include the following. The lexico-semantic structure of Yiddish is Slavic, and only the vocabulary is German. The number of German variants is determined by the Slavic substratum. When an Upper Sorbian word overlaps semantically only partially with a German root, the latter is used in Yiddish following the pattern of Upper Sorbian. The chapter contains five additional sections discussing the status of subsets of morphemes of the languages involved. The last chapter of the book, chap. 5, is dedicated to the discussion of topics for future research. Holes in the diachronic data are identified, both linguistic – resulting from the unavailability of data on relevant languages at relevant periods – and historical, resulting from a lack of studies on population movements for given periods. Holes in the comparative analysis of the languages involved are pointed out. As for the two-tiered relexification hypothesis involving two Slavic substratal languages, Upper Sorbian and Kiev-Polessian, in the formation of Yiddish, it is pointed out that the differential impact of these two grammars on Yiddish requires further study. Finally, the author calls for a comparison of the various cases of relexification in the languages of the world.

Wexler's book has the great merit of looking at a number of well-described facts in a way that departs significantly from the traditional ways of looking at them. Time will tell whether his relexification analysis will be shared by other scholars who work on the genesis of Yiddish and Modern Hebrew. For those who work on creole languages, this analysis comes as no surprise. Wexler's book also contains a number of quite interesting observations on the process of relexification, observations that immediately lead to new topics for research. For example, Wexler points out that in the makeup of Modern Hebrew, relexifiers ignored the lexifier language elements that are phonetically similar to those in their own language (section 3.3). This observation leads him to the conclusion that relexification is a prerequisite for conflation. This conclusion is in direct contrast to Kihm's (1989) and other authors' thesis (discussed by Wexler on p. 139) according to which conflation triggers relexification. The fact that there are opposite views calls for an explanation. Are the differences between them attributable to the differential situations in which the process of relexification takes place – that is, are they due to external factors, or to something else? Another observation by Wexler is that, in relexification, it is the morphologically least complex or unmarked German material that is selected by relexifiers. Denis 2004 has independently observed the same phenomenon in Haitian, a French-based creole. Why should this be so, given the fact that relexifiers do not always have much access to the lexifier language? The book contains several observations of this type that are worth looking at in light of other sets of data. Finally, owing to the methodology required to test the hypothesis of the book, a wealth of data drawn from the relevant languages involved are being compared in a way that they would never have been were it not for the hypothesis underlying the research. Moreover, through this comparison, systematic and principled similarities and differences reveal themselves.

There is one major drawback: The book is hard to read. Its structure as well as the mode of data presentation could have been improved so as to make the book more reader-friendly. A list of the languages involved as well as a short discussion of how they relate to one another would have been extremely useful for readers who are neither Slavicists nor Semiticists. The use of the expression “two-tiered relexification” is not always clear. Sometimes it appears to refer to relexification as taking place from two substratal grammars; sometimes it appears to refer to two successive relexifications from the same grammar but taking place at different times. This is a problem because both types have been attested. For example, Haitian Creole is the product of the relexification of several West African languages (see e.g. Lefebvre 1998; not just one, as is erroneously reported by Wexler on p. 11), having been relexified on the basis of French. The same is true of Papiamentu, a creole spoken in Aruba, Bonaire, and Curaçao, except that in this case, the West African languages have been relexified on the basis of Portuguese; the creole so formed has later been relexified again on the basis of Spanish (see, e.g., McWhorter 1995, Voorhoever1964). Wexler writes: “[M]any Caribbean creoles underwent two-tiered relexification first from African to Portuguese and then from Afro-Portuguese creole to a different European superstratum language” (552). Contrary to Wexler's claim, not “many” Caribbean creoles underwent two successive relexifications; to my knowledge, Papiamentu is the only such case reported in the literature.

In spite of these problems, the book is an important one for the reasons given above, and for the fact that it reports on another case of language genesis where relexification appears to have played a major role. In conclusion, a natural question that one can address to the author and that would link his work to the work of others on the topic is the following: If Yiddish is in fact the product of the relexification of several West African languages, Upper Sorbian and Kiev-Polessian, it should manifest some of the differences observed between these two grammars; assuming that this is the case, how are these differences hypothesized to be reconciled in Yiddish? Can a case be made for dialect leveling applying on the output of relexification on the basis of Yiddish, as it has been shown to apply in the case of other language contact varieties where relexification has played a major role (see Lefebvre 1998, Siegel 1997)?