Low-resource speech translation of Urdu to English using semi-supervised part-of-speech tagging and transliteration

This paper describes the construction of ASR and MT systems for translation of speech from Urdu into English. As both Urdu pronunciation lexicons and Urdu-English bitexts are sparse, we employ several techniques that make use of semi-supervised annotation to improve ASR and MT training. Specifically, we describe 1) the construction of a semi-supervised HMM-based part-of-speech tagger that is used to train factored translation models and 2) the use of an HMM-based transliterator from which we derive a spelling-to-pronunciation model for Urdu used in ASR training. We describe experiments performed for both ASR and MT training in the context of the Urdu-to-English task of the NIST MT08 Evaluation and we compare methods making use of additional annotation with standard statistical MT and ASR baselines.