Phonological naturalness and phonotactic learning

We investigate whether the patterns of phonotactic well-formedness internalized by language learners are direct reflections of the phonological patterns they encounter, or reflect in addition principles of phonological naturalness. As a research tool we employ the phonotactic learning system of Hayes and Wilson (2008), which carries out an unbiased search of the lexicon for valid phonotactic generalizations. Applying this system to English data, we find that it learns many constraints that seem to be unnatural—they have no evident typological or phonetic basis, yet hold true of the English lexicon. We tested the status of ten of these constraints in a nonce-probe study, obtaining nativespeaker ratings of novel words that violated them. We used 40 such words: 10 violating our unnatural constraints, 10 violating natural constraints assigned comparable weights by the Hayes/Wilson learner, and 20 violation-free forms, each similar to a test form and employed as a control. In our experiment, we found that violations of the natural constraints had a powerful effect on native speaker judgment and violations of the unnatural constraints had at best a weak one. We conclude by assessing a variety of hypotheses intended to explain this disparity, opting ultimately for a learning bias account. Author emails: [email protected], [email protected]. Thanks to Colin Wilson for advice, encouragement, and the use of his software, to Patricia Keating for making the recordings, and to our experimental participants for their patience. For helpful input and advice we thank Adam Albright, Robert Daland, Kie Zuraw; talk audiences at the UCLA, University of Alberta, Johns Hopkins University, Cornell University, and two extremely helpful LI reviewers. This study was supported by a grant from the Committee on Research of the UCLA Academic Senate. A web site with supplementary materials for this article is located at http://www.linguistics.ucla.edu/ people/hayes/PhonologicalNaturalness/. Hayes/White Phonological naturalness and phonotactic learning p. 2