Understanding near mergers : the case of morphological tone in Cantonese* Alan C. L. Yu University of Chicago A growing body of work on exemplar-based theories of learning suggests the possibility of formal models of phonological representation which will offer deeper explanations of basic phonological properties than current models allow. The main purpose of this paper is to shed light on near merger, a recalcitrant problem in sound change and in phonological theory, with this newer perspective, through a case study of tonal near merger in Cantonese. 1 Introduction A growing body of work on exemplar-based theories of learning suggests the possibility of formal models of phonological representation which will offer deeper explanations of basic phonological properties than current models allow. Exemplar-based models have proven useful not only in solving problems in phonetics and phonology (e.g. Pierrehumbert 1990, 2001, 2002, Goldinger 1996, Johnson 1997, Bybee 2001, Ernestus & Baayen 2003), but also in research domains as diverse as semantics, syn- tax, language acquisition and language change (see Gahl & Yu 2006 and references therein). The main purpose of this paper is to shed light from this newer perspective on near merger, a recalcitrant problem in sound change. Near merger describes the situation where speakers consistently report that two classes of sounds are ‘the same’, yet consistently differ- entiate them in production at better than chance level. Labov et al. (1972 : * During the preparation of this paper I benefited tremendously from discussions with (in alphabetical order) Rusty Barrett, Matt Goldrick, Bill Labov, Salikoko Mufwene and Janet Pierrehumbert. I would also like to thank audiences at the University of Pennsylvania, Northwestern University, University of Wisconsin, the Conference on Methods in Phonology at the University of California, Berkeley, and the Variation and Change in Phonology conference at Potsdam University. I would also like to thank Juliette Blevins and two anonymous reviewers for their discussion and criticism, which has led to considerable improvement of both the content and the presentation of my analysis. It goes without saying that any errors in this work are my own. Phonology 24 (2007) 187–214. f 2007 Cambridge University Press doi:10.1017/S0952675707001157 Printed in the United Kingdom 187