---
language:
- ibo
license: cc-by-nc-4.0
tags:
- text-to-speech
- tts
- vits
- mms
- nigerian-languages
- low-resource
- waxal
- soro-tts
- igbo
datasets:
- google/WaxalNLP
base_model: facebook/mms-tts-ibo
pipeline_tag: text-to-speech
library_name: transformers
metrics:
- cer
model-index:
- name: soro-tts-ibo
  results:
  - task:
      type: text-to-speech
      name: Text-to-Speech
    dataset:
      name: WAXAL TTS — Igbo
      type: google/WaxalNLP
      config: ibo_tts
      split: test
    metrics:
    - type: cer
      value: 44.84
      name: Character Error Rate (ASR-based)
---

# Soro-TTS — Igbo 🇳🇬

Part of **[Soro-TTS](https://huggingface.co/Shinzmann)**, a multilingual text-to-speech system for Nigerian languages.
This checkpoint is a fine-tune of [`facebook/mms-tts-ibo`](https://huggingface.co/facebook/mms-tts-ibo) on the
[`google/WaxalNLP`](https://huggingface.co/datasets/google/WaxalNLP) `ibo_tts` subset.

## Languages in the Soro-TTS suite
| Language | Model |
|---|---|
| Hausa | [`Shinzmann/soro-tts-hau`](https://huggingface.co/Shinzmann/soro-tts-hau) |
| Igbo | [`Shinzmann/soro-tts-ibo`](https://huggingface.co/Shinzmann/soro-tts-ibo) |
| Yoruba | [`Shinzmann/soro-tts-yor`](https://huggingface.co/Shinzmann/soro-tts-yor) |

## Quick start
```python
from transformers import VitsModel, AutoTokenizer
import torch, scipy.io.wavfile

model = VitsModel.from_pretrained("Shinzmann/soro-tts-ibo")
tokenizer = AutoTokenizer.from_pretrained("Shinzmann/soro-tts-ibo")

text = "Nnọọ na Naịjịrịa, obodo anyị nke jupụtara na ngọzi."
inputs = tokenizer(text, return_tensors="pt")

with torch.no_grad():
    waveform = model(**inputs).waveform[0].numpy()

scipy.io.wavfile.write("out.wav", rate=model.config.sampling_rate, data=waveform)
```

## Training data
Trained on the `ibo_tts` configuration of WAXAL — studio-quality, phonetically balanced single-speaker recordings collected by Media Trust under Google Research's WAXAL initiative.

| Statistic | Value |
|---|---|
| Total audio | 20.58 hours |
| Training audio | 17.28 hours (1552 clips) |
| Validation audio | 1.32 hours |
| Test audio | 1.98 hours |
| Speakers (train) | 8 |
| % words containing diacritics | 31.6% |
| Sample rate | 16 kHz |

## Architecture
VITS / MMS-TTS — a conditional VAE with adversarial training, a flow-based prior, and a HiFi-GAN-style decoder.
- **Parameters:** ~83M
- **Sample rate:** 16 kHz
- **Base model:** `facebook/mms-tts-ibo` (Pratap et al., 2023)

## Training procedure
| Hyperparameter | Value |
|---|---|
| Epochs | 100 |
| Batch size | 128 |
| Learning rate | 2e-05 |
| Optimizer | AdamW (β₁=0.8, β₂=0.99) |
| Precision | bf16 |
| Loss weights | mel=35, kl=1.5, gen=1, fmaps=1, disc=3, duration=1 |
| Recipe | [`ylacombe/finetune-hf-vits`](https://github.com/ylacombe/finetune-hf-vits) |

## Evaluation
**Character Error Rate (CER)** measured by transcribing synthesised audio with [`facebook/mms-1b-all`](https://huggingface.co/facebook/mms-1b-all) ASR (target_lang=`ibo`):

| Metric | n | Value |
|---|---|---|
| CER (ASR-based) | 20 | **44.84%** |

This proxy metric measures intelligibility, not naturalness. Human MOS evaluation by native speakers is recommended for the latter.

## Limitations and biases
- **Single voice.** WAXAL TTS is recorded by 1–2 professional voice actors per language. The model inherits that voice and accent.
- **Domain.** Training text covers news, narration, and read speech; conversational, code-switched, or highly informal text may be out of distribution.
- **Tonal nuance.** Igbo relies on tone marks for meaning. Inputs without proper diacritics will produce flat or incorrect prosody.
- **Non-commercial.** MMS-TTS base is **CC BY-NC 4.0**; this fine-tune inherits that license.

## License
CC BY-NC 4.0 (inherited from `facebook/mms-tts-ibo`). The WAXAL data itself is CC-BY-4.0.
**This model is for research only and may not be used commercially.**

## Citation
```bibtex
@misc{soro_tts_ibo_2026,
  title  = {{Soro-TTS: A Multilingual Text-to-Speech System for Nigerian Languages — Igbo}},
  author = {{Soro-TTS authors}},
  year   = {{2026}},
  url    = {{https://huggingface.co/Shinzmann/soro-tts-ibo}},
}
@article{pratap2023mms,
  title  = {{Scaling Speech Technology to 1{,}000+ Languages}},
  author = {{Pratap, Vineel and Tjandra, Andros and Shi, Bowen and others}},
  journal= {{arXiv:2305.13516}},
  year   = {{2023}}
}
```

## Acknowledgements
- Google Research and Media Trust for releasing WAXAL
- Meta AI for the MMS base models
- Yoach Lacombe for [`finetune-hf-vits`](https://github.com/ylacombe/finetune-hf-vits)