Modeling Morphological Subgeneralizations

Claire Moore-Cantwell,Robert Staubs

doi:10.3765/amp.v1i1.42

Claire Moore-Cantwell, Robert Staubs

Open Access

https://doi.org/10.3765/amp.v1i1.42

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Abstract

Exceptions to morphological regularities often pattern together phonologically. In the English past tense, exceptions to the regular ‘Add /-d/’ rule frequently inhabit ‘Islands of Reliability’ (Albright &amp; Hayes, 2003), in which a group of words take the same irregular past and also pattern together on a set of phonological characteristics. Adults seem to have implicit knowledge of both the overall pattern (the regular past) and the ‘subgeneralizations’.We model this knowledge of subgeneralizations through the interaction of a structured lexicon and a Maximum Entropy grammar. Words that pattern together with respect to a particular morphological process are grouped into a ‘bundle’, which is indexed to a constraint expressing the change that these words undergo to realize the morpheme. These ‘operational constraints’ compete with markedness and faithfulness in the phonological component. The phonological regularity of a bundle is represented by the average of constraint violations for members. Novel words are assigned a bundle on the basis of similarity to these averages.Our model shows promising correspondence with human data, including biases toward regularity and Island of Reliability effects. The model’s joint learning approach to phonology and morphology, as well as an inclusive concept of `context’, show promise for future application.

Highlights

Exceptions to morphological regularities often pattern together phonologically
Connectionist and analogical models have been criticized on the grounds that they don’t have a way to account for the generality of the phonology-morphology interaction (e.g. Pinker & Prince, 1988)
Operational constraint violations are assigned on the basis of this triple and the chosen bundle, markedness is assigned based on the surface representations (SR), and faithfulness is assigned based on the operations mapping underlying representation (UR) to SR

Summary

Introduction

Exceptions to morphological regularities often pattern together phonologically. In the English past tense system, exceptions to the regular ‘Add /-d/’ rule frequently inhabit ‘Islands of Reliability’ (Albright & Hayes, 2003), in which a group of words take the same irregular past and pattern together on a set of phonological characteristics. Bybee & Moder (1983), Prasada & Pinker (1993), and Albright & Hayes (2003) all conducted productivity tests of the English past tense system, finding that English speakers are most likely to choose a regular past for a novel verb, they occasionally produce irregulars (e.g. spling → splang). When they do, they respect the subgeneralizations, choosing the irregular past based on the behavior of words which are phonologically similar to the base. Each bundle has its own phonological representation which is the average of the representations of the lexical items in it, and a novel lexical item can choose which bundle to belong to based on its similarity to each bundle’s representation

Background

An integrated model of the lexicon and morphology

Testing the model’s performance

Conclusions