Why Catalan-Spanish Neural Machine Translation? Analysis, comparison and combination with standard Rule and Phrase-based technologies

Marta R. Costa-jussà


Abstract
Catalan and Spanish are two related languages given that both derive from Latin. They share similarities in several linguistic levels including morphology, syntax and semantics. This makes them particularly interesting for the MT task. Given the recent appearance and popularity of neural MT, this paper analyzes the performance of this new approach compared to the well-established rule-based and phrase-based MT systems. Experiments are reported on a large database of 180 million words. Results, in terms of standard automatic measures, show that neural MT clearly outperforms the rule-based and phrase-based MT system on in-domain test set, but it is worst in the out-of-domain test set. A naive system combination specially works for the latter. In-domain manual analysis shows that neural MT tends to improve both adequacy and fluency, for example, by being able to generate more natural translations instead of literal ones, choosing to the adequate target word when the source word has several translations and improving gender agreement. However, out-of-domain manual analysis shows how neural MT is more affected by unknown words or contexts.
Anthology ID:
W17-1207
Volume:
Proceedings of the Fourth Workshop on NLP for Similar Languages, Varieties and Dialects (VarDial)
Month:
April
Year:
2017
Address:
Valencia, Spain
Editors:
Preslav Nakov, Marcos Zampieri, Nikola Ljubešić, Jörg Tiedemann, Shevin Malmasi, Ahmed Ali
Venue:
VarDial
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
55–62
Language:
URL:
https://aclanthology.org/W17-1207
DOI:
10.18653/v1/W17-1207
Bibkey:
Cite (ACL):
Marta R. Costa-jussà. 2017. Why Catalan-Spanish Neural Machine Translation? Analysis, comparison and combination with standard Rule and Phrase-based technologies. In Proceedings of the Fourth Workshop on NLP for Similar Languages, Varieties and Dialects (VarDial), pages 55–62, Valencia, Spain. Association for Computational Linguistics.
Cite (Informal):
Why Catalan-Spanish Neural Machine Translation? Analysis, comparison and combination with standard Rule and Phrase-based technologies (Costa-jussà, VarDial 2017)
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PDF:
https://aclanthology.org/W17-1207.pdf