Frequency of violation and constraint-based phonological learning

This paper provides two arguments that error-driven constraint-based grammars should not be learned by directly mirroring the frequency of constraint violation and satisfaction in the target words of a language. The first argument comes from a class of stages attested in phonological development, called Intermediate Faith (IF) stages, in which children produce marked structures only in privileged positions. Two such stages are presented and analyzed, from the literature on English and French LI acquisition, and their learning consequences are examined. The second argument concerns the degree of restrictiveness that a learner's end-state grammar encodes, using two hypothetical interactions between learner's assumptions about hidden structure and developing constraint rankings that can trick a learner into adopting a superset grammar. These two arguments are used to support an approach called Error-Selective Learning (ESL), in which errors are learned and stored gradually, in a way that relics on violation frequency, but rankings themselves are learned in a non-gradual way (relying on the algorithms of Prince and Tesar, 2004; Hayes. 2004). It is also shown that violation frequencies can still cause problems regardless of a learner's method of grammatical evaluation-either ranked constraints as in Optimality Theory, or weighted constraints as in Harmonic Grammar. (C) 2008 Elsevier B.V. All rights reserved.