Overcoming the Rare Word Problem for Low-Resource Language Pairs in Neural Machine Translation
Table 5: The number of English OOV words are replaced by their synonyms.
['[EMPTY]', 'Train', 'tst2012', 'tst2013']
Similarly to the Japanese→Vietnamese system, we apply LSW algorithm on the English texts from (4) while selecting 1-best synonym for each OOV word. Again, we obtained a bigger gain of +0.99 (+1.02) BLEU points in English→Vietnamese direction. Compared to the most recent work Huang2018, our system reports an improvement of +0.47 standard BLEU points on the same dataset.