Left Behind: Cross-Lingual Transfer as a Bridge for Low-Resource Languages in Large Language Models
Organizations: North American University
Abstract
We investigate how large language models perform on low-resource languages by benchmarking eight LLMs across five experimental conditions in English, Kazakh, and Mongolian. Using 50 hand-crafted questions spanning factual, reasoning, technical, and culturally grounded categories, we evaluate 2,000 responses on accuracy, fluency, and completeness. We find a consistent performance gap of 13.8-16.7 percentage points between English and low-resource language conditions, with models maintaining surface-level fluency while producing significantly less accurate content. Cross-lingual transfer-prompting models to reason in English before translating back-yields selective gains for bilingual architectures (+2.2pp to +4.3pp) but provides no benefit to English-dominant models. Our results demonstrate that current LLMs systematically underserve low-resource language communities, and that effective mitigation strategies are architecture-dependent rather than universal.
Figures & tables
| Condition | Total | Acc. | Flu. | Comp. | Time | Len. |
|---|---|---|---|---|---|---|
| C1: English | 90.7 | 78.5 | 100.0 | 93.6 | 7.3 | 237 |
| C2: Kazakh Dir. | 76.9 | 65.5 | 89.0 | 76.1 | 14.6 | 128 |
| C3: Kazakh CLT | 77.2 | 67.1 | 88.6 | 76.0 | 35.4 | 79 |
| C4: Mongol. Dir. | 74.0 | 62.7 | 87.5 | 71.8 | 25.0 | 143 |
| C5: Mongol. CLT | 74.6 | 64.8 | 86.6 | 72.5 | 18.5 | 86 |
| Cat. | Cond. | Score | CLT | Time | Len. |
| Eng.-First | C1 | 92.2 | — | 7.2 | 231 |
| C2 | 88.2 | 1.1 | 11.8 | 130 | |
| C3 | 87.1 | 11.0 | 80 | ||
| C4 | 87.3 | 0.7 | 25.4 | 137 | |
| C5 | 86.7 | 14.7 | 89 | ||
| Bilingual | C1 | 91.2 | — | 6.4 | 251 |