Minimum Risk Training for Neural Machine Translation
Table 3: Case-insensitive BLEU scores on Chinese-English translation.
['System', 'Training', 'MT06', 'MT02', 'MT03', 'MT04', 'MT05', 'MT08']
For RNNsearch, we follow Luong et al. \shortciteLuong:15 to handle rare words. We find that introducing minimum risk training into neural MT leads to surprisingly substantial improvements over Moses and RNNsearch with MLE as the training criterion (up to +8.61 and +7.20 BLEU points, respectively) across all test sets. All the improvements are statistically significant.