SkMTEB: Slovak Massive Text Embedding Benchmark and Model Adaptation

Marek Suppa, Andrej Ridzik, Daniel Hl\'adek, Nat\'alia K\v{n}a\v{z}ekov\'a, Vikt\'oria Ondrejov\'a


Abstract
We introduce SkMTEB, the first comprehensive MTEB-style text embedding benchmark for Slovak, a low-resource West Slavic language, comprising 31 datasets across 7 task types—nearly 4× the depth of existing multilingual benchmark coverage for Slovak. Our evaluation of 31 embedding models reveals that large instruction-tuned multilingual models achieve the strongest performance, while existing Slovak-specific models trained for NLU tasks transfer poorly to embedding tasks. To address the need for efficient, locally-deployable Slovak embeddings, we develop (45M parameters) and (365M) by applying vocabulary trimming and fine-tuning to Multilingual E5 models. Despite size reductions of up to 62%, our open-source models achieve competitive performance with proprietary APIs while remaining locally deployable for semantic search and retrieval-augmented generation (RAG). We release the benchmark, models, datasets, and code openly, hoping our approach offers a replicable path for other under-resourced languages.
Anthology ID:
2026.acl-long.2114
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
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ACL
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Publisher:
Association for Computational Linguistics
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Pages:
45597–45628
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.2114/
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Cite (ACL):
Marek Suppa, Andrej Ridzik, Daniel Hl\'adek, Nat\'alia K\v{n}a\v{z}ekov\'a, and Vikt\'oria Ondrejov\'a. 2026. SkMTEB: Slovak Massive Text Embedding Benchmark and Model Adaptation. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 45597–45628, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
SkMTEB: Slovak Massive Text Embedding Benchmark and Model Adaptation (Suppa et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.2114.pdf
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