sk-bench: A Native-First Benchmark for Evaluating Large Language Models in Slovak
Organizations: Comenius University in Bratislava, Slovakia · Cisco Systems · Kempelen Institute of Intelligent Technologies, Bratislava, Slovakia · Brno University of Technology, Czechia · Technical University of Košice, Slovakia
Abstract
Multilingual LLM benchmarks omit Slovak, a morphologically rich West Slavic language of five million speakers, or cover it only by machine translation. We present sk-bench, a native-first Slovak benchmark with 30 datasets (33 scored task variants) across ten skill categories. Eleven resources are introduced or first packaged for generative-LLM evaluation, including IFEval-SK with Slovak-adapted instruction checkers and native Chiby/SKJ1 resources for Slovak grammar and morphology. We evaluate 55 open- and closed-weights models under one harness. The best open model trails proprietary APIs by 12.6 points. Model rankings are similar for native and translated closed-form data (), though translation separates the strongest models less well. By contrast, human-authored and LLM-generated QA questions rank models differently (). For Qwen3-14B, continued Slovak pretraining lowers the overall score by 13.9 points. A small instruction set restores three quarters of that loss. Test-time reasoning improves scores by 8.5 to 12.5 points for models of 9B and above. Together, these findings suggest four design lessons for other under-resourced languages: use native data where translation fails, plan instruction repair after language adaptation, enable test-time reasoning before scaling up, and avoid overinvesting in target-language prompts. We release the data and code at https://github.com/slovak-nlp/sk-bench
Figures & tables
| Model | Knowledge & reasoning | Reading & QA | Classification | Generation | Instruction following | Grammar & morphology | Overall |
| 2B | |||||||
| Granite 4.0-H 1B | 39.8 0.6 | 28.2 0.6 | 50.1 7.8 | 14.8 0.9 | 14.9 | 6.0 0.8 | 25.6 1.8 |
| Qwen3 1.7B | 35.0 5.5 | 30.9 2.8 | 52.4 7.8 | 12.8 0.9 | 23.5 | 12.3 1.9 | 27.8 2.4 |
| 2–9B | |||||||
| Ministral 3 8B | 60.4 1.3 | 39.2 6.2 | 70.6 4.4 | 13.5 0.8 | 24.0 | 37.1 1.0 | 40.8 2.3 |
| Ministral 3 8B (R) | 54.9 1.9 | 37.8 4.0 | 61.9 7.2 | 13.1 1.1 | 39.9 | 32.1 2.8 | 39.9 2.4 |
| Within parameter band | ||||||||
| Contrast | Overall | 2B | 2–9B | 9–32B | 32–200B | 200B | Prop. | top-10 |
| NLI (N vs MT) | 0.99 | 0.93 | 0.99 | 0.98 | 0.96 † | 0.90 † | 0.94 † | 10/10 |
| MCQ (N vs MT) | 0.98 | 0.93 | 0.96 | 0.98 | 0.93 † | 0.40 † | 0.71 † | 7/10 |
| QA (N vs G) | 0.72 | 0.17 | 0.43 | 0.74 | 0.64 † | 0.80 † | 0.94 † | 6/10 |
Appendix figures & tables21 assets
Supplementary material from the paper’s appendix.
Appendix
| Overall | by group | ||||||
| Lineage | Base | +Alp. | Know. | Class. | Instr. | Gram. | |
| Mistral-SK 7B | 19.0 | 14.9 | -4.0 | -1.1 | -16.9 | -0.4 | +4.9 |
| Qwen3-SK 14B | 33.5 | 43.8 | +10.3 | +26.6 | +16.5 | +13.2 | -19.8 |
| TildeOpen-SK 30B | 31.9 | 32.8 | +0.8 | -0.6 | -29.2 | +11.5 | +30.7 |
| Overall | by group | |||||
| Model | Std | Think | Instr. | Gram. | Gen. | |
| Qwen3 0.6B | 21.5 | 27.2 | +5.7 | +19.6 | +1.1 | -0.3 |
| Qwen3.5 0.8B† | 24.0 | 7.2 | -16.8 | +10.1 | +3.6 | -9.4 |
| Qwen3 1.7B | 27.8 | 40.0 | +12.2 | +23.8 | +10.2 | -1.0 |
| Qwen3.5 2B† | 29.4 | 19.8 | -9.7 | +7.1 | +12.5 | -10.8 |
| Qwen3.5 9B | 47.9 | 56.4 | +8.5 | +21.2 | +28.8 | -3.5 |
| Reporting group | SK | EN | |
| Knowledge & Reasoning | 58.1 | 58.3 | +0.1 |
| Reading & QA | 39.4 | 41.0 | +1.6 |
| Classification | 61.3 | 61.1 | -0.2 |
| Generation | 13.2 | 13.1 | -0.1 |
| Grammar & Morphology | 33.5 | 30.9 | -2.6 |
| Overall | 49.9 | 50.3 | +0.4 |
| skLEP | BCM | MERA | HuLU | INCL | sk-bench | |
| Language | sk | cs | ru | hu | multi | sk |
| Generative LLM eval | ✓ | ✓ | ✓ | ✓ | ||
| Native paired contrast | ✓ | |||||
| Open + closed, one harness | ✓ | |||||
| Grammar & morphology | ✓ | |||||
| Instruction-following | ✓ |
| Context | SK | EN | |
| 4,096 | 58.1 | 60.5 | -2.4 |
| 8,192 | 55.6 | 56.4 | -0.7 |
| 16,384 | 54.4 | 53.4 | +1.1 |
| Slovak | English | |||
| Reporting group | 0-shot | 3-shot | 0-shot | 3-shot |
| Knowledge & reasoning | 60.6 | 59.4 | 61.2 | 60.4 |
| Reading & QA | 29.4 | 32.6 | 30.7 | 33.6 |
| Classification | 61.9 | 66.8 | 61.3 | 67.0 |
| Grammar & morphology | 35.7 | 36.8 | 28.6 | 27.0 |
| Overall | 46.9 | 48.9 | 45.4 | 47.0 |
| Model | Input Tokens [M] | Completion Tokens [M] | Total Tokens [M] | Cost | Evaluation Time [hours] |
| Open-source Models | |||||
| ibm-granite/granite-4.0-h-350m | 457.03 | 7.27 | 464.29 | N/A | 4.17 |
| ibm-granite/granite-4.0-350m | 457.03 | 10.83 | 467.85 | N/A | 1.97 |
| Qwen/Qwen3-0.6B | 439.36 | 14.13 | 453.49 | N/A | 2.49 |
| Qwen/Qwen3.5-0.8B | 369.88 | 13.04 | 382.92 | N/A | 3.16 |
| google/gemma-3-1b-it | 361.46 | 8.33 | 369.79 | N/A | 2.22 |
| Dataset | Prov. | Skill | Licence | Description | |
|---|---|---|---|---|---|
| SentiSK | 4,677 | N | sentiment | CC BY-SA 4.0 | Slovak user-text sentiment corpus used in binary and 3-class settings. Neutral examples are excluded from the binary score. |
| MovieReview | 2,008 | N | sentiment | — | Slovak film- and series-review sentiment with labels derived from user star ratings ( Štefánik et al., 2023 ) , included as a second native binary sentiment source. See Appendix D.3 . |
| skLEP-sentiment | 1,042 | N | sentiment | Mixed | The sentiment subtask from skLEP, retained as a small validation cross-check against the larger sentiment resources. |
| ToxicSK | 881 | N | safety classification | CC BY-SA 3.0 | Slovak toxicity-detection corpus scored as yes/no classification. |
| skLEP-hate | 1,319 | N | safety classification | Mixed | skLEP hate-speech subtask, paired with ToxicSK to separate toxicity from explicit hate-speech labelling. |
| NLI-SK-annotated | 597 | N | NLI | — | Human-annotated Slovak 3-way entailment dataset after filtering the non-NLI “Other” category. |
| Skill | Native side | Contrast side |
| NLI | NLI-SK-annotated | skLEP-NLI (MT) |
| Multiple-choice | e-testy-sk , | Okapi-MMLU-SK (MT) |
| knowledge | Slovak-tests | |
| Question answering | skLEP-QA (human) | MultiWikiQA-SK (G) |
| Grammar & morph. | Chiby , SKJ1 , | translation cannot |
| Slohry | produce these |
| Model | Params. | Licence | Reported cutoff | # Langs | HF SHA | Ref. |
| ibm-granite/granite-4.0-h-350m | 350M | Apache 2.0 | — | 12 | 3b17b717b8f2f5d305b0a92c1491e239aeda19c8 | ( Granite Team, IBM, 2024 ) |
| ibm-granite/granite-4.0-350m | 350M | Apache 2.0 | — | 12 | bd8a1497065c0d6ba1ef19af6b0d2b14bacf71c2 | ( Granite Team, IBM, 2024 ) |
| Qwen/Qwen3-0.6B | 0.6B | Apache 2.0 | — | 100+ | c1899de289a04d12100db370d81485cdf75e47ca | ( Yang et al., 2025 ) |
| Qwen/Qwen3.5-0.8B | 0.8B | Apache 2.0 | — | 201 | 2fc06364715b967f1860aea9cf38778875588b17 | ( Yang et al., 2025 ) |
| google/gemma-3-1b-it | 1B | gemma | — | 140+ | dcc83ea841ab6100d6b47a070329e1ba4cf78752 | ( Team et al., 2025a ) |
| ibm-granite/granite-4.0-h-1b | 1B | Apache 2.0 | — | 12 | d18cca4c121edb87d022116d281ce212c9136f57 | ( Granite Team, IBM, 2024 ) |
| Group (examples) | Source published | Split previously released? | Underlying source public? |
| Newly packaged here (Chiby, Slohry, OneRuler-SK, Scio, Autoškola, e-testy-sk, Slovak-tests, Word Analogies, Slovak Trivia) | 2024–2026 | No — evaluation split first assembled for sk-bench | Often yes (public exams, Wikipedia, dictionary) |
| Previously released native (NLI-SK-annotated, SK-QuAD, skLEP, SlovakSum, SME-Sum) | 2020–2026 | Yes | Yes |
| Translated proxies (Okapi-MMLU-SK, ARC-SK, TruthfulQA-SK, Belebele-SK, SlovakCOPA) | English 2018–2022, Slovak 2023–2024 | Yes | Yes (English originals ubiquitous) |
| LLM-generated (MultiWikiQA-SK) | 2025, over a 2023 Wikipedia dump | Yes | Yes (Wikipedia) |
| Model | Knowledge & reasoning | Reading & QA | Classification | Generation | Instruction following | Grammar & morphology | Overall |
|---|---|---|---|---|---|---|---|
| 2B | |||||||
| Granite 4.0 350M | 27.5 3.1 | 10.1 0.6 | 13.8 10.3 | 9.7 3.4 | 10.8 | 1.8 1.3 | 12.3 1.9 |
| Granite 4.0-H 350M | 25.5 5.7 | 9.4 0.9 | 27.3 10.1 | 11.7 2.0 | 15.3 | 1.3 0.0 | 15.1 3.2 |
| Qwen3 0.6B | 33.1 5.2 | 20.9 3.5 | 43.3 7.5 | 10.6 0.2 | 16.8 | 4.2 1.3 | 21.5 1.6 |
| Qwen3.5 0.8B | 33.4 2.8 | 26.0 0.3 | 53.5 7.8 | 9.7 0.2 | 14.3 | 7.0 2.5 | 24.0 1.3 |
| Gemma 3 1B | 35.1 2.0 | 19.9 3.0 | 54.4 4.1 | 11.8 1.0 | 12.3 | 3.0 0.8 | 22.7 0.6 |
| Model | ARC | MMLU | G-MMLU | TruthQA | SCIO | FinExam | Driving | COPA | SKJ1 | Trivia | Belebele | Chiby | WikiQA | ETest-M | ETest-Q | SKTest-M | SKTest-Q | OneRuler | skLEP-QA | NLI | skLEP-NLI | skLEP-RTE | Senti-3 | Senti-2 | skLEP-Sent | MovieRev | Toxic | skLEP-Hate | SlovakSum | SME-Sum | IFEval | Analogies | Slohry | Avg |
| 2B | ||||||||||||||||||||||||||||||||||
| Granite 4.0 350M | 26.5 | 27.7 | 26.7 | 21.9 | 25.9 | 25.9 | 33.2 | 48.7 | 12.7 | 26.1 | 30.0 | 0.9 | 3.6 | 19.4 | 0.2 | 25.4 | 1.3 | 7.2 | 3.0 | 7.3 | 7.1 | 5.2 | 28.5 | 22.0 | 23.8 | 25.6 | 3.1 | 1.4 | 9.8 | 9.6 | 10.8 | 0.3 | 3.2 | 15.9 |
| Granite 4.0-H 350M | 24.1 | 26.6 | 25.6 | 13.8 | 21.8 | 22.3 | 32.2 | 50.5 | 15.3 | 22.4 | 26.7 | 2.7 | 1.7 | 20.0 | 0.2 | 26.9 | 0.8 | 0.5 | 4.9 | 4.0 | 3.9 | 14.9 | 43.3 | 67.4 | 10.3 | 52.5 | 41.2 | 8.2 | 10.8 | 12.6 | 15.3 | 0.0 | 2.6 | 19.0 |
| Qwen3 0.6B | 25.9 | 25.9 | 26.2 | 65.3 | 21.4 | 31.0 | 61.1 | 49.4 | 3.3 | 21.1 | 34.2 | 26.8 | 1.2 | 20.9 | 0.5 | 29.0 | 1.5 | 56.0 | 17.6 | 23.4 | 21.2 | 36.1 | 28.3 | 75.8 | 33.8 | 58.6 | 56.3 | 56.6 | 11.6 | 9.7 | 16.8 | 2.6 | 5.9 | 28.9 |
| Qwen3.5 0.8B | 41.1 | 33.1 | 35.8 | 28.5 | 28.7 | 34.5 | 54.7 | 50.1 | 2.7 | 24.6 | 47.1 | 43.9 | 14.9 | 25.4 | 0.9 | 36.8 | 1.3 | 50.5 | 13.4 | 24.7 | 22.8 | 56.7 | 67.5 | 85.2 | 57.6 | 69.0 | 57.7 | 40.2 | 10.9 | 8.5 | 14.3 | 7.3 | 6.7 | 33.2 |
| Gemma 3 1B | 27.3 | 28.4 | 32.8 | 52.8 | 23.5 | 35.0 | 70.0 | 51.8 | 2.7 | 26.9 | 34.0 | 34.7 | 13.7 | 21.7 | 2.6 | 35.9 | 2.1 | 13.9 | 20.1 | 22.2 | 24.2 | 51.7 | 65.2 | 81.5 | 82.0 | 73.1 | 56.1 | 33.3 | 12.0 | 11.7 | 12.3 | 2.0 | 4.0 | 32.2 |
| Model | ARC | MMLU | G-MMLU | TruthQA | SCIO | FinExam | Driving | COPA | SKJ1 | Trivia | Belebele | Chiby | WikiQA | ETest-M | ETest-Q | SKTest-M | SKTest-Q | OneRuler | skLEP-QA | NLI | skLEP-NLI | skLEP-RTE | Senti-3 | Senti-2 | skLEP-Sent | MovieRev | Toxic | skLEP-Hate | SlovakSum | SME-Sum | IFEval | Analogies | Slohry | Avg |
| 2B | ||||||||||||||||||||||||||||||||||
| Qwen3 0.6B | 39.1 | 34.5 | 33.2 | 29.3 | 30.6 | 40.4 | 53.7 | 53.1 | 7.0 | 26.7 | 46.7 | 46.1 | 10.3 | 26.8 | 2.9 | 31.1 | 2.4 | 49.3 | 18.7 | 36.9 | 38.6 | 64.9 | 35.1 | 47.2 | 79.5 | 65.5 | 54.8 | 31.8 | 11.2 | 9.6 | 36.3 | 4.5 | 6.1 | 33.5 |
| Qwen3.5 0.8B | 7.1 | 2.8 | 2.3 | 0.6 | 2.5 | 1.7 | 3.6 | 1.9 | 0.0 | 0.3 | 1.2 | 0.1 | 0.0 | 4.1 | 0.1 | 2.3 | 0.8 | 0.5 | 0.0 | 2.5 | 3.2 | 0.3 | 2.9 | 4.5 | 15.2 | 6.1 | 3.9 | 2.5 | 0.3 | 0.2 | 24.4 | 2.3 | 18.9 | 3.6 |
| Qwen3 1.7B | 67.5 | 51.6 | 53.9 | 36.9 | 49.5 | 49.6 | 59.4 | 68.8 | 22.0 | 31.4 | 72.0 | 51.1 | 25.1 | 42.4 | 14.8 | 43.7 | 5.6 | 93.2 | 23.5 | 54.8 | 57.2 | 76.1 | 49.3 | 63.4 | 92.0 | 81.1 | 71.2 | 68.7 | 12.0 | 11.7 | 47.3 | 22.2 | 22.8 | 48.2 |
| 2–9B | ||||||||||||||||||||||||||||||||||
| Qwen3.5 2B | 42.9 | 31.2 | 25.8 | 10.9 | 23.9 | 24.7 | 31.9 | 13.5 | 1.3 | 4.9 | 29.9 | 18.8 | 21.3 | 18.5 | 1.4 | 13.5 | 1.4 | 26.9 | 23.5 | 20.6 | 18.2 | 23.8 | 20.3 | 26.2 | 62.6 | 41.7 | 26.4 | 24.3 | 0.5 | 0.3 | 25.9 | 23.7 | 25.7 | 21.4 |
| Model | ARC | MMLU | G-MMLU | TruthQA | SCIO | FinExam | Driving | COPA | SKJ1 | Trivia | Belebele | Chiby | WikiQA | ETest-M | ETest-Q | SKTest-M | SKTest-Q | OneRuler | skLEP-QA | NLI | skLEP-NLI | skLEP-RTE | Senti-3 | Senti-2 | skLEP-Sent | MovieRev | Toxic | skLEP-Hate | SlovakSum | SME-Sum | Analogies | Avg |
| 2B | ||||||||||||||||||||||||||||||||
| Granite 4.0 350M | 26.3 | 27.0 | 25.4 | 7.5 | 27.7 | 24.7 | 19.0 | 50.3 | 0.0 | 26.5 | 32.0 | 50.3 | 6.4 | 20.6 | 0.6 | 28.1 | 1.3 | 16.8 | 8.5 | 34.4 | 31.2 | 53.8 | 46.6 | 74.8 | 59.9 | 70.8 | 46.7 | 72.7 | 8.2 | 9.0 | 0.9 | 29.3 |
| Granite 4.0-H 350M | 25.5 | 27.8 | 25.9 | 7.6 | 24.3 | 25.3 | 25.7 | 50.7 | 48.3 | 22.9 | 28.7 | 50.2 | 6.3 | 22.4 | 0.6 | 20.2 | 0.8 | 24.7 | 14.3 | 25.2 | 23.7 | 44.5 | 62.5 | 87.4 | 30.4 | 65.4 | 47.3 | 67.0 | 11.1 | 15.1 | 0.3 | 30.1 |
| Qwen3 0.6B | 29.9 | 29.5 | 29.0 | 30.2 | 23.8 | 32.6 | 65.5 | 48.5 | 7.7 | 24.1 | 39.6 | 50.7 | 8.1 | 24.7 | 0.3 | 30.5 | 1.1 | 52.3 | 18.6 | 32.3 | 29.6 | 52.5 | 65.9 | 66.8 | 46.2 | 55.7 | 53.3 | 28.0 | 12.4 | 12.5 | 2.0 | 32.4 |
| Qwen3.5 0.8B | 40.5 | 32.8 | 37.8 | 48.9 | 27.6 | 37.1 | 60.5 | 50.6 | 0.0 | 26.1 | 53.5 | 51.4 | 19.5 | 25.8 | 1.0 | 37.6 | 1.7 | 37.3 | 15.0 | 31.6 | 28.7 | 60.0 | 64.8 | 85.8 | 57.2 | 67.2 | 64.4 | 67.6 | 12.4 | 11.9 | 1.1 | 37.3 |
| Gemma 3 1B | 32.0 | 31.3 | 36.9 | 39.8 | 26.7 | 35.6 | 65.8 | 51.5 | 1.7 | 28.6 | 37.1 | 52.0 | 14.5 | 24.1 | 1.7 | 35.9 | 2.2 | 20.1 | 15.2 | 44.4 | 43.3 | 65.3 | 66.7 | 87.2 | 60.1 | 72.5 | 63.6 | 46.8 | 10.1 | 10.2 | 1.3 | 36.3 |
| Model | ARC | MMLU | G-MMLU | Scio | Driving | COPA | SKTest-M | SKTest-Q | skLEP-QA | skLEP-NLI | skLEP-RTE | Senti-3 | Senti-2 | skLEP-Sent | MovieRev | Toxic | skLEP-Hate | Analogies | Slohry | Avg |
| 2B | ||||||||||||||||||||
| Granite 4.0 350M | 24.6 | 27.8 | 27.1 | 23.9 | 24.9 | 49.1 | 26.2 | 1.0 | 10.1 | 24.9 | 42.2 | 16.1 | 21.2 | 36.8 | 48.0 | 41.8 | 62.9 | 0.5 | 1.5 | 26.9 |
| Granite 4.0-H 350M | 24.3 | 25.4 | 26.0 | 24.4 | 59.0 | 49.9 | 30.7 | 1.5 | 9.4 | 26.9 | 49.0 | 67.9 | 85.6 | 22.8 | 58.8 | 31.1 | 44.6 | 0.1 | 0.4 | 33.6 |
| Qwen3 0.6B | 35.5 | 31.8 | 32.7 | 26.5 | 36.5 | 43.5 | 33.9 | 1.1 | 15.1 | 35.7 | 45.2 | 47.0 | 84.6 | 51.8 | 59.1 | 54.9 | 46.9 | 0.7 | 8.8 | 36.4 |
| Qwen3.5 0.8B | 40.1 | 33.6 | 34.2 | 26.1 | 32.3 | 50.5 | 29.8 | 2.1 | 11.6 | 36.6 | 57.2 | 51.6 | 78.1 | 76.2 | 73.7 | 54.6 | 33.6 | 4.1 | 9.0 | 38.7 |
| Gemma 3 1B | 28.2 | 30.0 | 33.0 | 25.0 | 65.0 | 51.5 | 33.1 | 1.8 | 17.0 | 35.4 | 58.6 | 49.9 | 61.5 | 91.5 | 80.1 | 54.1 | 47.8 | 0.6 | 3.4 | 40.4 |
| Model | ARC | MMLU | G-MMLU | Scio | Driving | COPA | SKTest-M | SKTest-Q | skLEP-QA | skLEP-NLI | skLEP-RTE | Senti-3 | Senti-2 | skLEP-Sent | MovieRev | Toxic | skLEP-Hate | Avg | |
| 2B | |||||||||||||||||||
| Granite 4.0 350M | 26.3 | 28.0 | 29.2 | 25.3 | 22.2 | 49.9 | 28.6 | 1.3 | 11.4 | 34.2 | 50.3 | 12.7 | 70.0 | 90.1 | 70.3 | 46.4 | 72.7 | 0.2 | 37.2 |
| Granite 4.0-H 350M | 27.1 | 27.6 | 28.1 | 28.9 | 31.3 | 50.6 | 30.7 | 1.1 | 11.1 | 31.0 | 55.1 | 55.1 | 87.3 | 64.1 | 60.0 | 47.0 | 72.5 | 0.2 | 39.4 |
| Qwen3 0.6B | 36.8 | 34.1 | 34.3 | 29.6 | 30.7 | 53.3 | 31.8 | 2.1 | 15.5 | 36.7 | 55.2 | 44.1 | 81.0 | 83.0 | 67.6 | 55.7 | 63.7 | 0.4 | 42.0 |
| Qwen3.5 0.8B | 43.3 | 35.0 | 37.6 | 28.6 | 48.7 | 51.9 | 31.6 | 1.7 | 14.6 | 36.7 | 60.4 | 48.7 | 76.6 | 89.6 | 74.7 | 57.9 | 71.5 | 0.6 | 45.0 |
| Gemma 3 1B | 30.5 | 29.9 | 33.6 | 24.0 | 67.9 | 52.4 | 35.8 | 2.2 | 18.1 | 40.3 | 61.5 | 50.6 | 64.4 | 91.5 | 78.0 | 72.7 | 67.4 | 0.9 | 45.7 |