Salute the Classic: Revisiting Challenges of Machine Translation in the Age of Large Language Models

Jianhui Pang, Fanghua Ye, Derek Fai Wong, Dian Yu, Shuming Shi, Zhaopeng Tu, Longyue Wang


Abstract
The evolution of Neural Machine Translation (NMT) has been significantly influenced by six core challenges (Koehn and Knowles, 2017) that have acted as benchmarks for progress in this field. This study revisits these challenges, offering insights into their ongoing relevance in the context of advanced Large Language Models (LLMs): domain mismatch, amount of parallel data, rare word prediction, translation of long sentences, attention model as word alignment, and sub-optimal beam search. Our empirical findings show that LLMs effectively reduce reliance on parallel data for major languages during pretraining and significantly improve translation of long sentences containing approximately 80 words, even translating documents up to 512 words. Despite these improvements, challenges in domain mismatch and rare word prediction persist. While NMT-specific challenges like word alignment and beam search may not apply to LLMs, we identify three new challenges in LLM-based translation: inference efficiency, translation of low-resource languages during pretraining, and human-aligned evaluation.
Anthology ID:
2025.tacl-1.4
Volume:
Transactions of the Association for Computational Linguistics, Volume 13
Month:
Year:
2025
Address:
Cambridge, MA
Venue:
TACL
SIG:
Publisher:
MIT Press
Note:
Pages:
73–95
Language:
URL:
https://aclanthology.org/2025.tacl-1.4/
DOI:
10.1162/tacl_a_00730
Bibkey:
Cite (ACL):
Jianhui Pang, Fanghua Ye, Derek Fai Wong, Dian Yu, Shuming Shi, Zhaopeng Tu, and Longyue Wang. 2025. Salute the Classic: Revisiting Challenges of Machine Translation in the Age of Large Language Models. Transactions of the Association for Computational Linguistics, 13:73–95.
Cite (Informal):
Salute the Classic: Revisiting Challenges of Machine Translation in the Age of Large Language Models (Pang et al., TACL 2025)
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PDF:
https://aclanthology.org/2025.tacl-1.4.pdf