Token and Type Constraints for Cross-Lingual Part-of-Speech Tagging

Täckström, Oscar and Das, Dipanjan and Petrov, Slav and McDonald, Ryan and Nivre, Joakim (2013) Token and Type Constraints for Cross-Lingual Part-of-Speech Tagging. Transactions of the Association for Computational Linguistics, 1 . pp. 1-12.

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We consider the construction of part-of-speech taggers for resource-poor languages. Recently, manually constructed tag dictionaries from Wiktionary and dictionaries projected via bitext have been used as type constraints to overcome the scarcity of annotated data in this setting. In this paper, we show that additional token constraints can be projected from a resource-rich source language to a resource-poor target language via word-aligned bitext. We present several models to this end; in particular a partially observed conditional random field model, where coupled token and type constraints provide a partial signal for training. Averaged across eight previously studied Indo-European languages, our model achieves a 25% relative error reduction over the prior state of the art. We further present successful results on seven additional languages from different families, empirically demonstrating the applicability of coupled token and type constraints across a diverse set of languages.

Item Type:Article
ID Code:5472
Deposited By:Oscar Tackström
Deposited On:22 Mar 2013 15:53
Last Modified:22 Mar 2013 15:53

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