Published online by Cambridge University Press: 14 August 2017
This paper examines a key difference between constraint conjunction and constraint weight additivity, arguing that the two do not have the same empirical coverage. In particular, constraint conjunction in weighted probabilistic grammar allows for superadditive constraint interaction, where the effect of violating two constraints goes beyond the additive combination of the two constraints’ weights alone. A case study from parasitic tone harmony in Dioula d'Odienné demonstrates superadditive local and long-distance segmental feature similarities that increase the likelihood of tone harmony. Superadditivity in Dioula d'Odienné is formally captured in Maximum Entropy Harmonic Grammar by weighted constraint conjunction. Counter to previous approaches that supplant constraint conjunction with weight additivity in Harmonic Grammar, information-theoretic model comparison reveals that weighted constraint conjunction improves the grammar's explanatory power when modelling quantitative natural language patterns.
Acknowledgements to Kie Zuraw, Eric Bakovi«, Christopher Green, Lauren Hall-Lew, Gunnar Hansson, Sharon Inkelas, Laura McPherson, Joe Pater, Brian Smith, Anne-Michelle Tessier, Colin Wilson and audiences at WCCFL 33, GLOW 38 and UCs Merced and Berkeley for discussion on various portions of this work. Thanks also to Jeff Heinz and Bill Idsardi, and two anonymous reviewers for detailed comments. Errors are inevitable in stochastic systems, and the author accepts blame for any that remain herein.