Add cross-language evaluation matrix (4-model × 4-language study)

README.md

@@ -238,4 +238,37 @@ If you use this model in your research or project, please cite:
 
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-*If this model helped your project, consider giving it a ⭐ — it helps others find it too!*
+*If this model helped your project, consider giving it a ⭐ — it helps others find it too!*
+
+---
+
+## 📊 Cross-Language Evaluation
+
+Each model was evaluated on all 4 languages (300 sentences per language, 100 per class).
+This shows how well models trained on one language transfer to others.
+
+### Accuracy Matrix
+
+| Model | English | Hindi | Maithili | Bhojpuri |
+|---|---|---|---|---|
+| ⭐ **English model** _(this model)_ | **79.5%** ✓ | 34.0% | 33.3% | 33.0% |
+| **Hindi model** | 60.0% | **68.0%** ✓ | 63.3% | 61.7% |
+| **Maithili model** | 63.0% | 59.0% | **90.3%** ✓ | 75.0% |
+| **Bhojpuri model** | 59.0% | 47.3% | 47.3% | **98.0%** ✓ |
+
+### F1 Matrix (macro)
+
+| Model | English | Hindi | Maithili | Bhojpuri |
+|---|---|---|---|---|
+| ⭐ **English model** _(this model)_ | **0.5424** ✓ | 0.1912 | 0.1667 | 0.1654 |
+| **Hindi model** | 0.4362 | **0.6778** ✓ | 0.6319 | 0.6042 |
+| **Maithili model** | 0.4443 | 0.5757 | **0.9035** ✓ | 0.7458 |
+| **Bhojpuri model** | 0.4250 | 0.4166 | 0.4114 | **0.9801** ✓ |
+
+### Key Findings
+
+- This model achieves **79.5%** on English sentiment but drops to **~33%** on Maithili and Bhojpuri — equivalent to random chance on a 3-class task.
+- Demonstrates that monolingual English training does **not** transfer to low-resource Bihari languages.
+- English also transfers poorly to Hindi (34%), confirming the language barrier extends beyond Bihari languages.
+
+> **Full paper:** This cross-evaluation is part of a research study on cross-lingual transfer for low-resource Bihari languages. See the companion datasets and models: [Maithili](https://huggingface.co/abhiprd20/maithili-sentiment-model) | [Bhojpuri](https://huggingface.co/abhiprd20/bhojpuri-sentiment-model) | [Hindi](https://huggingface.co/abhiprd20/hindi-sentiment-model) | [English](https://huggingface.co/abhiprd20/nlp-sentiment-model)