APE at Scale and Its Implications on MT Evaluation Biases

Markus Freitag, Isaac Caswell, Scott Roy


Abstract
In this work, we train an Automatic Post-Editing (APE) model and use it to reveal biases in standard MT evaluation procedures. The goal of our APE model is to correct typical errors introduced by the translation process, and convert the “translationese” output into natural text. Our APE model is trained entirely on monolingual data that has been round-trip translated through English, to mimic errors that are similar to the ones introduced by NMT. We apply our model to the output of existing NMT systems, and demonstrate that, while the human-judged quality improves in all cases, BLEU scores drop with forward-translated test sets. We verify these results for the WMT18 English to German, WMT15 English to French, and WMT16 English to Romanian tasks. Furthermore, we selectively apply our APE model on the output of the top submissions of the most recent WMT evaluation campaigns. We see quality improvements on all tasks of up to 2.5 BLEU points.
Anthology ID:
W19-5204
Volume:
Proceedings of the Fourth Conference on Machine Translation (Volume 1: Research Papers)
Month:
August
Year:
2019
Address:
Florence, Italy
Editors:
Ondřej Bojar, Rajen Chatterjee, Christian Federmann, Mark Fishel, Yvette Graham, Barry Haddow, Matthias Huck, Antonio Jimeno Yepes, Philipp Koehn, André Martins, Christof Monz, Matteo Negri, Aurélie Névéol, Mariana Neves, Matt Post, Marco Turchi, Karin Verspoor
Venue:
WMT
SIG:
SIGMT
Publisher:
Association for Computational Linguistics
Note:
Pages:
34–44
Language:
URL:
https://aclanthology.org/W19-5204
DOI:
10.18653/v1/W19-5204
Bibkey:
Cite (ACL):
Markus Freitag, Isaac Caswell, and Scott Roy. 2019. APE at Scale and Its Implications on MT Evaluation Biases. In Proceedings of the Fourth Conference on Machine Translation (Volume 1: Research Papers), pages 34–44, Florence, Italy. Association for Computational Linguistics.
Cite (Informal):
APE at Scale and Its Implications on MT Evaluation Biases (Freitag et al., WMT 2019)
Copy Citation:
PDF:
https://aclanthology.org/W19-5204.pdf