Morphological Segmentation Inside-Out

TL;DR

This paper introduces a discriminative, joint model for hierarchical morphological segmentation that captures derivational structures and orthographic changes, supported by a new annotated English word treebank.

Contribution

It presents the first context-free, discriminative model for hierarchical morphological segmentation and provides an annotated treebank for future research.

Findings

First hierarchical morphological segmentation model

Jointly models orthographic changes and segmentation

Provides an annotated English word treebank

Abstract

Morphological segmentation has traditionally been modeled with non-hierarchical models, which yield flat segmentations as output. In many cases, however, proper morphological analysis requires hierarchical structure -- especially in the case of derivational morphology. In this work, we introduce a discriminative, joint model of morphological segmentation along with the orthographic changes that occur during word formation. To the best of our knowledge, this is the first attempt to approach discriminative segmentation with a context-free model. Additionally, we release an annotated treebank of 7454 English words with constituency parses, encouraging future research in this area.