The model is created by adapting a wav2vec2.0-based encoder to the embedding space of NLLB, using a novel subword compression module and Optimal Transport, while only utilizing ASR data. It thus enables Zero-shot E2E Speech Translation to all the 200 languages supported by NLLB.

For more details please refer to our paper and the original repo build on fairseq.

Architecture

The compression module is a light-weight transformer that takes as input the hidden state of wav2vec2.0 and the corresponding CTC predictions, and compresses them to subword-like embeddings similar to those expected from NLLB and aligns them using Optimal Transport. For inference we simply pass the output of the speech encoder to NLLB encoder.

Version

This version of ZeroSwot is trained with ASR data from CommonVoice. It adapts wav2vec2.0-large to the embedding space of the nllb-200-distilled-1.3B_covost2 model, which is a multilingually finetuned NLLB on MuST-C MT data.

We have more versions available:

Models	ASR data	NLLB version
ZeroSwot-Medium_asr-mustc	MuST-C v1.0	distilled-600M original
ZeroSwot-Medium_asr-mustc_mt-mustc	MuST-C v1.0	distilled-600M finetuned w/ MuST-C
ZeroSwot-Large_asr-mustc	MuST-C v1.0	distilled-1.3B original
ZeroSwot-Large_asr-mustc_mt-mustc	MuST-C v1.0	distilled-1.3B finetuned w/ MuST-C
ZeroSwot-Medium_asr-cv	CommonVoice	distilled-600M original
ZeroSwot-Medium_asr-cv_mt-covost2	CommonVoice	distilled-600M finetuned w/ CoVoST2
ZeroSwot-Large_asr-cv	CommonVoice	distilled-1.3B original
ZeroSwot-Large_asr-cv_mt-covost2	CommonVoice	distilled-1.3B finetuned w/ CoVoST2

Usage

The model is tested with python 3.9.16 and Transformer v4.41.2. Install also torchaudio and sentencepiece for processing.

pip install transformers torchaudio sentencepiece

python

from transformers import Wav2Vec2Processor, NllbTokenizer, AutoModel, AutoModelForSeq2SeqLM
import torchaudio

def load_and_resample_audio(audio_path, target_sr=16000):
    audio, orig_freq = torchaudio.load(audio_path)
    if orig_freq != target_sr:
        audio = torchaudio.functional.resample(audio, orig_freq=orig_freq, new_freq=target_sr)
    audio = audio.squeeze(0).numpy()
    return audio

# Load processors and tokenizers
processor = Wav2Vec2Processor.from_pretrained("facebook/wav2vec2-large-960h-lv60-self")
tokenizer = NllbTokenizer.from_pretrained("johntsi/nllb-200-distilled-1.3B_covost2_en-to-15")

# Load ZeroSwot Encoder
commit_hash = "762878c55bf91406318983c724db22590a828e96"
zeroswot_encoder = AutoModel.from_pretrained(
    "johntsi/ZeroSwot-Large_asr-cv_mt-covost2_en-to-15", trust_remote_code=True, revision=commit_hash,
)
zeroswot_encoder.eval()
zeroswot_encoder.to("cuda")

# Load NLLB Model
nllb_model = AutoModelForSeq2SeqLM.from_pretrained("johntsi/nllb-200-distilled-1.3B_covost2_en-to-15")
nllb_model.eval()
nllb_model.to("cuda")

# Load audio file
audio = load_and_resample_audio(path_to_audio_file) # you can use "resources/sample.wav" for testing
input_values = processor(audio, sampling_rate=16000, return_tensors="pt").to("cuda")

# translation to German
compressed_embeds, attention_mask = zeroswot_encoder(**input_values)
predicted_ids = nllb_model.generate(
    inputs_embeds=compressed_embeds,
    attention_mask=attention_mask,
    forced_bos_token_id=tokenizer.lang_code_to_id["deu_Latn"],
    num_beams=5,
)
translation = tokenizer.decode(predicted_ids[0], skip_special_tokens=True)
print(translation)

Results

BLEU scores on CoVoST-2 test compared to supervised SOTA models XLS-R-2B and SeamlessM4T-Large. You can refer to Table 5 of the Results section in the paper for more details.

Models	ZS	Size (B)	Ar	Ca	Cy	De	Et	Fa	Id	Ja	Lv	Mn	Sl	Sv	Ta	Tr	Zh	Average
XLS-R-2B	✗	2.0	20.7	34.2	33.8	28.3	24.1	22.9	32.5	41.5	23.5	16.2	27.6	34.5	19.8	18.6	38.5	27.8
SeamlessM4T-L-v1	✗	2.3	24.5	41.6	33.6	35.9	28.5	19.3	39.0	39.4	23.8	15.7	35.0	42.5	22.7	23.9	33.1	30.6
SeamlessM4T-L-v2	✗	2.3	25.4	43.6	35.5	37.0	29.3	19.2	40.2	39.7	24.8	16.4	36.2	43.7	23.4	24.7	35.9	31.7
ZeroSwot-Large_asr-cv	✓	0.35/1.65	19.8	36.1	22.6	31.8	23.6	16.8	34.2	33.6	17.5	11.8	28.9	36.8	19.1	17.5	32.2	25.5
ZeroSwot-Large_asr-cv_mt-covost2	✓	0.35/1.65	25.7	40.0	29.0	32.8	27.2	26.6	37.1	47.1	25.7	18.9	33.2	39.3	25.3	19.8	40.5	31.2

Citation

If you find ZeroSwot useful for your research, please cite our paper :)

@inproceedings{tsiamas-etal-2024-pushing,
    title = {{Pushing the Limits of Zero-shot End-to-End Speech Translation}},
    author = "Tsiamas, Ioannis  and
      G{\'a}llego, Gerard  and
      Fonollosa, Jos{\'e}  and
      Costa-juss{\`a}, Marta",
    editor = "Ku, Lun-Wei  and
      Martins, Andre  and
      Srikumar, Vivek",
    booktitle = "Findings of the Association for Computational Linguistics ACL 2024",
    month = aug,
    year = "2024",
    address = "Bangkok, Thailand and virtual meeting",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/2024.findings-acl.847",
    pages = "14245--14267",
}