A hierarchical phrase-based model for English-Persian statistical machine translation

In this paper we show that a hierarchical phrase-based translation system will outperform a classical (non-hierarchical) phrase-based system in the English-to-Persian translation direction, yet for the Persian-to-English direction, the classical phrase-based system is preferable. We seek to explain why this is so, and detail a series of translation experiments with our SMT system using various bilingual corpora each with both toolkits Moses (non-hierarchical) and Joshua (hierarchical).