---
license: cc-by-nc-4.0
language:
- es
- zap
pipeline_tag: translation
tags:
- translation
- nllb
- zapotec
- diidxaza
- low-resource
base_model: facebook/nllb-200-distilled-600M
library_name: transformers
---

# Spanish → Isthmus Zapotec (diidxazá) translator

Neural machine translation from Spanish (`spa_Latn`) into Isthmus Zapotec
(diidxazá), built by LoRA fine-tuning
[`facebook/nllb-200-distilled-600M`](https://huggingface.co/facebook/nllb-200-distilled-600M)
and merging the adapter back into the base for a standalone model.

Isthmus Zapotec is not covered by any pretrained MT model, so an existing NLLB
language slot (`ayr_Latn`) is reused as the Zapotec output tag. Every training
target is Zapotec, so the model fully repurposes that tag. The forced target tag
is stored in `generation_config.json` (`forced_bos_token_id`), so generation
needs no special setup.

## Usage

```python
from transformers import AutoModelForSeq2SeqLM, AutoTokenizer

model_id = "simpleverso/espzap-nllb-600m"
model = AutoModelForSeq2SeqLM.from_pretrained(model_id)
tok = AutoTokenizer.from_pretrained(model_id, src_lang="spa_Latn")

inputs = tok("Buenos días, ¿cómo estás?", return_tensors="pt")
out = model.generate(**inputs, num_beams=4, max_length=96)
print(tok.batch_decode(out, skip_special_tokens=True)[0])
```

## Results

Trained for 6 epochs on 18,452 unique parallel pairs.

| Metric | Dev (best epoch) | Test (held-out) |
|---|---|---|
| chrF | 42.1 | 37.7 |
| BLEU | 9.7  | 6.4  |

chrF is the more meaningful metric: Zapotec is morphologically rich, and
character-level scoring rewards correct aspect prefixes (`hr-`, `bi-`, `na-`) and
person suffixes (`-lu'`, `-tu'`, `-a'`).

## Limitations

- Trained on ~18.5k pairs; usable but imperfect.
- Part of the training data (a poems PDF) is unreviewed, so some outputs may
  reflect noise in that source.
- Handles everyday sentences best; long or highly literary input degrades.

## License

The base model NLLB-200 is released under CC-BY-NC-4.0; this derivative inherits
that non-commercial license.