Neural machine translation (briefly, NMT) (Bahdanau et al., 2014;Gehring et al., 2017;Vaswani et al., 2017) is well-known for its outstanding performance (Hassan et al., 2018), which usually relies on large-scale bitext for training.
when turning to clean tuning, we can obtain another 1.2 and 2.3 points improvement.