COMI-LINGUA-MLI

Model Card for Model ID

Model Description

This is a fine-tuned version of aya-expanse-8b for Matrix Language Identification (MLI) on Hinglish (Hindi-English code-mixed) text. It classifies each sentence at the sentence level into the dominant matrix language governing the grammatical structure: hi (Hindi) or en (English).

The model handles mixed Roman and Devanagari scripts and is optimized for identifying the primary syntactic framework in natural code-mixed sentences.

Achieves 98.77 F1 on the COMI-LINGUA MLI test set (5K instances), outperforming zero-shot closed LLMs (e.g., gpt-4o: ~98.0 F1) and traditional tools, and setting SOTA among open-weight models.

• Model type: LoRA-adapted Transformer LLM (8B params, ~32M trainable)
• Language(s) (NLP): Hindi, English
• License: apache-2.0
• Finetuned from model: CohereForAI/aya-expanse-8b

Model Sources

• Paper: COMI-LINGUA: Expert Annotated Large-Scale Dataset for Multitask NLP in Hindi-English Code-Mixing
• Demo: Integrated in Demo Portal

Uses

• Sentence-level MLI in Hinglish pipelines (e.g., preprocessing for downstream tasks like translation, sentiment analysis, or code-switching detection in social media/news).

• Helps determine the dominant language structure for better handling of code-mixed content.

• Example inference prompt:

Identify the matrix language (hi = Hindi matrix, en = English matrix) in: "PM Narendra Modi ne Google CEO Sundar Pichai se mulakat ki."
Output: 'hi'  

Training Details

Training Data

COMI-LINGUA Dataset Card.

Training Procedure

Preprocessing

Tokenized with base tokenizer; instruction templates + few-shot examples. Filtered: ≥5 tokens, no hate/non-Hinglish, balanced matrix languages.

Training Hyperparameters

• Regime: PEFT LoRA (rank=32, alpha=64, dropout=0.1)
• Epochs: 3
• Batch: 4 (accum=8, effective=32)
• LR: 2e-4 (cosine + warmup=0.1)
• Weight decay: 0.01

Evaluation

Testing Data

COMI-LINGUA MLI test set (5K instances).

Metrics

Macro Precision / Recall / F1 (sentence-level).

Results

Summary: Near-perfect performance on MLI; fine-tuning pushes open-weight models to near-ceiling accuracy, outperforming zero/one-shot LLMs and establishing SOTA for Hinglish matrix language detection.

Bias, Risks, and Limitations

<span style="color:red"> This model is a research preview and is subject to ongoing iterative updates. As such, it provides only limited safety measures.</span>

May struggle with highly balanced code-mixing (no clear matrix), rare syntactic patterns, or domain shift outside news/social media. Some zero-shot LLMs showed format instability (e.g., outputting 'Mixed' instead of 'hi'/'en'); fine-tuning resolves this.

Model Card Contact

Lingo Research Group at IIT Gandhinagar, India </br> Mail at: [email protected]

Citation

If you use this model, please cite the following work:

@inproceedings{sheth-etal-2025-comi,
    title = "{COMI}-{LINGUA}: Expert Annotated Large-Scale Dataset for Multitask {NLP} in {H}indi-{E}nglish Code-Mixing",
    author = "Sheth, Rajvee  and
      Beniwal, Himanshu  and
      Singh, Mayank",
    editor = "Christodoulopoulos, Christos  and
      Chakraborty, Tanmoy  and
      Rose, Carolyn  and
      Peng, Violet",
    booktitle = "Findings of the Association for Computational Linguistics: EMNLP 2025",
    month = nov,
    year = "2025",
    address = "Suzhou, China",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/2025.findings-emnlp.422/",
    pages = "7973--7992",
    ISBN = "979-8-89176-335-7",
}