Source-Side Suffix Stripping for Bengali-to-English SMT

Data sparseness is a well-known problem for statistical machine translation (SMT) when morphologically rich and highly inflected languages are involved. This problem become worse in resource-scarce scenarios where sufficient parallel corpora are not available for model training. Recent research has shown that morphological segmentation can be employed on either side of the translation pair to reduce data sparsity. In this work, we consider a highly inflected Indian language as the source-side of the translation pair, Bengali. This paper presents study of morphological segmentation in SMT with a less explored translation pair, Bengali-to-English. We worked with a tiny training set available for this language-pair. We employ a simple suffix-stripping method for lemmatizing inflected Bengali words. We show that our morphological suffix separation process significantly reduces data sparseness. We also show that an SMT model trained on suffix-stripped (source) training data significantly outperforms the state-of-the-art phrase-based SMT (PB-SMT) baseline.