Model Overview

This model can be used for translating text in source language (En) to a text in target language (Zh).

Model Architecture

The model is based on Transformer "Big" architecture originally presented in "Attention Is All You Need" paper [1]. In this particular instance, the model has 24 layers in the encoder and 6 layers in the decoder. It is using YouTokenToMe tokenizer [2].

Training

These models were trained on a collection of many publicly available datasets comprising hundreds of millions of parallel sentences. The NeMo toolkit [5] was used for training this model over roughly 500k steps.

Datasets

While training this model, we used the following datasets:

• News-Commentary http://data.statmt.org/news-commentary/v15/training/news-commentary-v15.en-zh.tsv.gz
• WikiTitles - http://data.statmt.org/wikititles/v2/wikititles-v2.zh-en.tsv.gz
• WikiMatrix - http://data.statmt.org/wmt20/translation-task/WikiMatrix/WikiMatrix.v1.en-zh.langid.tsv.gz
• Backtranslated Chinese - http://data.statmt.org/wmt20/translation-task/back-translation/zh-en/news.translatedto.zh.gz
• Backtranslated English - http://data.statmt.org/wmt20/translation-task/back-translation/zh-en/news.en.gz
• CC-Aligned - http://www.statmt.org/cc-aligned/sentence-aligned/en_XX-zh_CN.tsv.xz
• CC-Matrix - https://github.com/facebookresearch/LASER/tree/master/tasks/CCMatrix
• Paracrawl - http://data.statmt.org/wmt21/translation-task/zh-en/paracrawl.wmt21.en-zh.gz

Tokenizer Construction

We used the YouTokenToMe tokenizer [2] with separate encoder and decoder BPE tokenizers.

Performance

The accuracy of translation models are often measured using BLEU scores [3]. The model achieves the following sacreBLEU [4] scores on the WMT'18, WMT'19 and WMT'20 test sets

WMT18 - 39.9
WMT19 - 32.8
WMT20 - 40.2

How to Use this Model

The model is available for use in the NeMo toolkit [5], and can be used as a pre-trained checkpoint for inference or for fine-tuning on another dataset.

Automatically load the model from NGC

import nemo
import nemo.collections.nlp as nemo_nlp
nmt_model = nemo_nlp.models.machine_translation.MTEncDecModel.from_pretrained(model_name="nmt_en_zh_transformer24x6")

Translating text with this model

python [NEMO_GIT_FOLDER]/examples/nlp/machine_translation/nmt_transformer_infer.py --model=nmt_en_zh_transformer24x6.nemo --srctext=[TEXT_IN_SRC_LANGUAGE] --tgtout=[WHERE_TO_SAVE_TRANSLATIONS] --target_lang zh --source_lang en

Input

This translate method of the NMT model accepts a list of de-tokenized strings.

Output

The translate method outputs a list of de-tokenized strings in the target language.

Limitations

No known limitations at this time.

References

[1] Vaswani, Ashish, et al. "Attention is all you need." arXiv preprint arXiv:1706.03762 (2017).

[2] https://github.com/VKCOM/YouTokenToMe

[3] https://en.wikipedia.org/wiki/BLEU

[4] https://github.com/mjpost/sacreBLEU

[5] NVIDIA NeMo Toolkit

Licence

License to use this model is covered by the NGC TERMS OF USE unless another License/Terms Of Use/EULA is clearly specified. By downloading the public and release version of the model, you accept the terms and conditions of the NGC TERMS OF USE.