Unsupervised Part-of-Speech Tagging with Bilingual Graph-Based Projections

Dipanjan Das1 and Slav Petrov2
1Carnegie Mellon University, 2Google Research


Abstract

We describe a novel approach for inducing unsupervised part-of-speech taggers for languages that have no labeled training data, but have translated text in a resource-rich language. Our method does not assume any knowledge about the target language (in particular no tagging dictionary is assumed), making it applicable to a wide array of resource-poor languages. We use graph-based label propagation for cross-lingual knowledge transfer and use the projected labels as features in an unsupervised model (Berg-Kirkpatrick et al., 2010). Across eight European languages, our approach results in an average absolute improvement of 10.4% over a state-of-the-art baseline, and 16.7% over vanilla hidden Markov models induced with the Expectation Maximization algorithm.




Full paper: http://www.aclweb.org/anthology/P/P11/P11-1061.pdf