An Empirical Study of Many-Shot In-Context Learning for Machine Translation of Low-Resource Languages

Yinhan Lu, Gaganpreet Jhajj, Chen Zhang, Anietie Andy, David Ifeoluwa Adelani


Abstract
In-context learning (ICL) allows large language models (LLMs) to adapt to new tasks from a few examples, making it promising for languages underrepresented in pre-training. Recent work on many-shot ICL suggests that modern LLMs can further benefit from more ICL examples enabled by their long context windows. However, the inference cost can be prohibitive for low-resource language communities, and it is unclear whether example selection can reduce the number of examples needed. In this paper, we present a systematic empirical study of many-shot ICL for machine translation from English into ten truly low-resource languages recently added to FLORES+. We analyze the effects of retrieving more informative examples, using out-of-domain data, and ordering examples. Our findings show that many-shot ICL becomes more effective as the number of examples increases. More importantly, we show that BM25 retrieval substantially improves data efficiency: 50 retrieved examples roughly match 250 many-shot examples, while 250 retrieved examples approach the performance of 1,000 many-shot examples. We further show that example ordering has little effect and that ICL provides additional gains on top of fine-tuning.
Anthology ID:
2026.findings-aacl.142
Volume:
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2772–2804
Language:
URL:
https://aclanthology.org/2026.findings-aacl.142/
DOI:
Bibkey:
Cite (ACL):
Yinhan Lu, Gaganpreet Jhajj, Chen Zhang, Anietie Andy, and David Ifeoluwa Adelani. 2026. An Empirical Study of Many-Shot In-Context Learning for Machine Translation of Low-Resource Languages. In Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026, pages 2772–2804, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
An Empirical Study of Many-Shot In-Context Learning for Machine Translation of Low-Resource Languages (Lu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-aacl.142.pdf