Andrew Nevins (2010). Locality in vowel harmony . (Linguistic Inquiry Monograph 55.) Cambridge, Mass.:MIT Press. Pp. xii+244.

A viable analysis of any phenomenon must achieve at least two conditions of adequacy (Chomsky 1965: 27). It must be descriptively adequate, in the sense that it correctly describes the phenomenon; it captures the linguistic facts. More importantly, it must aim for explanatory adequacy, in the sense that the theory that engenders the analysis explains why the phenomenon has the properties ascribed to it and not others. There are many analyses of vowel harmony that, on the surface, achieve the level of descriptive adequacy, but do not qualify as explanatory because they do not address the question of what is a possible vowel harmony system. This question must be addressed if an analysis can claim to be explanatory. This monograph, Locality in vowel harmony, meets this test. At the level of description, Nevins provides deeply insightful analyses of an impressive range of vowel harmony systems. At the level of explanation, he proposes a theory that sharply circumscribes what is a possible vowel harmony system, ruling out certain logical possibilities in a principled manner. A comprehensive analysis of vowel harmony is not the real goal of this monograph. The overarching and ultimate goal is to show that the locality conditions that regulate the manifestation of vowel harmony can be attributed to the same principle that regulates long-distance syntactic dependencies such as the familiar agreement relations. Hence, vowel harmony is considered to be another instance of Agree (Chomsky 2000). The investigation of vowel harmony as a manifestation of the Agree relation is part of an overarching goal to show that (some aspects of) phonology can be characterised in terms of the principles of the Strong Minimalist Program, the goal of which is to show that language provides optimal solutions to interface conditions. The monograph contains six chapters, including an introduction and a final summary that considers some of the implications of the theory of harmony, and speculates on the types of experiments that would help to test its validity. The introductory chapter provides an overview of the theory of vowel harmony. Nevins rejects the conventional approach that analyses the phenomenon as a process that transmits a feature value rightwards, leftwards or bidirectionally from a donor to a recipient. His proposed alternative is a SEARCH-AND-COPY theory, in which some vowel that lacks a particular feature value seeks a source that can provide that value. Crucially, the search is always minimal, in the sense that the feature-source is always the closest possible donor. For Nevins, ‘vowel harmony emerges as a computational operation whose purpose is to provide a solution for valuing [an] ‘uninterpretable’ o vowel through the principle of minimal search for the closest goal to act as a feature-source’ (p. 12). The determination of closest depends on what the needy element is looking for. Nevins argues that, crosslinguistically, locality can be relativised ‘to certain types of properties of Phonology 28 (2011) 530–537. f Cambridge University Press 2011 doi:10.1017/S0952675711000261