  The University of Edinburgh participated in the WMT19 Shared Task on News
Translation in six language directions: English-to-Gujarati,
Gujarati-to-English, English-to-Chinese, Chinese-to-English, German-to-English,
and English-to-Czech. For all translation directions, we created or used
back-translations of monolingual data in the target language as additional
synthetic training data. For English-Gujarati, we also explored semi-supervised
MT with cross-lingual language model pre-training, and translation pivoting
through Hindi. For translation to and from Chinese, we investigated
character-based tokenisation vs. sub-word segmentation of Chinese text. For
German-to-English, we studied the impact of vast amounts of back-translated
training data on translation quality, gaining a few additional insights over
Edunov et al. (2018). For English-to-Czech, we compared different
pre-processing and tokenisation regimes.
