Automatic Machine Translation Detection Using a Surrogate Multilingual Translation Model

Cristian García-Romero, Miquel Esplà-Gomis, Felipe Sánchez-Martínez


Abstract
Modern machine translation (MT) systems depend on large parallel corpora, often collected from the Internet. However, recent evidence indicates that (i) a substantial portion of these texts are machine-generated translations, and (ii) an overreliance on such synthetic content in training data can significantly degrade translation quality. As a result, filtering out non-human translations is becoming an essential pre-processing step in building high-quality MT systems. In this work, we propose a novel approach that directly exploits the internal representations of a surrogate multilingual MT model to distinguish between human and machine-translated sentences. Experimental results show that our method outperforms current state-of-the-art techniques, particularly for non-English language pairs, achieving gains of at least 5 percentage points of accuracy.
Anthology ID:
2026.tacl-1.55
Volume:
Transactions of the Association for Computational Linguistics, Volume 14
Month:
Year:
2026
Address:
Cambridge, MA
Venue:
TACL
SIG:
Publisher:
MIT Press
Note:
Pages:
1225–1242
Language:
URL:
https://aclanthology.org/2026.tacl-1.55/
DOI:
10.1162/tacl.a.704
Bibkey:
Cite (ACL):
Cristian García-Romero, Miquel Esplà-Gomis, and Felipe Sánchez-Martínez. 2026. Automatic Machine Translation Detection Using a Surrogate Multilingual Translation Model. Transactions of the Association for Computational Linguistics, 14:1225–1242.
Cite (Informal):
Automatic Machine Translation Detection Using a Surrogate Multilingual Translation Model (García-Romero et al., TACL 2026)
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PDF:
https://aclanthology.org/2026.tacl-1.55.pdf