The LMU Munich System for the WMT 2021 Large-Scale Multilingual Machine Translation Shared Task

Wen Lai, Jindřich Libovický, Alexander Fraser

WMT 2021

This paper describes the submission of LMU Munich to the WMT 2021
multilingual machine translation task for small track #1, which
studies translation between 6 languages (Croatian, Hungarian,
Estonian, Serbian, Macedonian, English) in 30 directions. We
investigate the extent to which bilingual translation systems can
influence multilingual translation systems. More specifically, we
trained 30 bilingual translation systems, covering all language pairs,
and used data augmentation technologies such as back-translation and
knowledge distillation to improve the multilingual translation
systems. Our best translation system scores 5 to 6 BLEU higher than a
strong baseline system provided by the organizers. As seen in the
dynalab leaderboard, our submission is the only fully constrained
submission that uses only the corpus provided by the organizers and
does not use any pre-trained models.