Malagasy OCP Targets a Single Affix: Implications for Morphosyntactic Generalization in Learning

1 Introduction

Investigators have uncovered evidence for phonological learning biases: biases inherent in learners that favor certain language phonologies over others (e.g., Wilson 2006, Finley 2012, Moreton and Pater 2012, Hayes and White 2013, McMullin and Hansson 2014, White 2014). To what extent can a learning bias be defied in language? This question bears directly on the theory of phonological learning, as it addresses the limits of learner capability.

A growing family of findings suggests that learners tend to favor phonological constraints that are morphosyntactically general—that is, obeyed by at least several morphemes, or in multiple or all grammatical contexts. That phonological alternations are typically corroborated by the phonotactics of a given language was observed as early as Chomsky and Halle 1968 and Kenstowicz and Kisseberth 1977, but the generalizing tendency just mentioned has also been observed in a number of recent corpus studies. Martin (2007, 2011), Shih and Zuraw (2018), and Breiss and Hayes (2019) observe cases of grammatical "leaking," in which strong phonotactic restrictions tend to manifest across word boundaries or compound boundaries, or affect the choice between grammatical constructions. Chong (2017) found that certain alternations purported to be apparent derived-environment effects are just that—merely apparent. For example, though Korean t-palatalization triggered by high front vocoids was previously proposed to constitute a derived-environment effect because [ti]-sequences exist in some roots, Chong showed that such sequences are highly underattested in the Korean lexicon. Generalization effects have also been borne out in artificial-language-learning experiments: Myers and Padgett (2014) found that participants generalize a phrase-final devoicing pattern to the word-final domain without exposure to unambiguous evidence; Chong (2017) found that participants more readily learned a suffixal harmony alternation when they were exposed to higher rates of root harmony, corroborating proposals that phonotactic generalizations assist in acquiring alternations (e.g., Tesar and Prince 2003, Hayes 2004, Jarosz 2006).

In light of these findings, Martin (2011) and Chong (2017) propose learning models whereby whenever the learner weights positively a structure-specific constraint (e.g., applying only across a suffix boundary), it gives positive weight to an analogous structure-insensitive constraint, leading to the generalizing tendency. If there were to exist an alternation that applies consistently in a constrained morphosyntactic context without even an analogous statistical tendency in phonotactics to accompany it, then that would complicate our understanding of learners' preference for morphosyntactically general patterns, as it would suggest that wholly structure-specific alternations could be learned.

This squib presents one such alternation. Malagasy displays backness dissimilation, an alternation that has persisted across multiple generations that sends a back vowel to front in the presence of a nearby back vowel. The process applies very consistently to the passive imperative suffix, -u, and is blocked by intervening front vowels—a behavior typical of dissimilation—suggesting the working of an OCP (Obligatory Contour Principle) constraint. But -u is the only affix in the language that undergoes dissimilation, and is the only suffix even eligible to undergo it. Moreover, stems in the lexicon show no preference for dissimilation whatsoever; they in fact display a modest but highly significant opposing preference for harmony. This suggests that Malagasy learners induce a morphologically specific OCP constraint—specific either to -u alone or to the suffix domain as a whole—without the need for a corroborating phonotactic trend. These findings suggest that no degree of morphosyntactic generality is a necessary condition for learning. Though learners might be biased toward acquiring grammatically general constraints, the Malagasy system suggests that they are capable of overriding it. I present this system below, and discuss the problems it poses for a theory in which learners favor grammatically general constraints.

2 Backness Dissimilation Applying to the Passive Imperative Suffix

Unless otherwise specified, the data below come from the Malagasy Dictionary and Encyclopedia of Madagascar (hereafter MDEM; malagasyword.org; de La Beaujardière 2004), an annotated online corpus containing approximately 92,000 Malagasy words. The Malagasy vowel inventory is composed of [i e a u] (Parker 1883, MDEM 2004). There are four suffixes: the passive suffixes -in# and -#n...