A unified framework for phrase-based, hierarchical, and syntax-based statistical machine translation Hieu Hoang author Philipp Koehn author Adam Lopez author 2009-dec 1-2 text Proceedings of the 6th International Workshop on Spoken Language Translation: Papers Tokyo, Japan conference publication hoang-etal-2009-unified https://aclanthology.org/2009.iwslt-papers.4/ 2009-dec 1-2 152 159