AraBERT v1 & v2 : Pre-training BERT for Arabic Language Understanding

AraBERT is an Arabic pretrained lanaguage model based on Google's BERT architechture. AraBERT uses the same BERT-Base config. More details are available in the AraBERT Paper and in the AraBERT Meetup

There are two versions of the model, AraBERTv0.1 and AraBERTv1, with the difference being that AraBERTv1 uses pre-segmented text where prefixes and suffixes were splitted using the Farasa Segmenter.

We evalaute AraBERT models on different downstream tasks and compare them to mBERT, and other state of the art models (To the extent of our knowledge). The Tasks were Sentiment Analysis on 6 different datasets (HARD, ASTD-Balanced, ArsenTD-Lev, LABR), Named Entity Recognition with the ANERcorp, and Arabic Question Answering on Arabic-SQuAD and ARCD


What's New!

AraBERT now comes in 4 new variants to replace the old v1 versions:

More Detail in the AraBERT folder and in the README and in the AraBERT Paper

Model HuggingFace Model Name Size (MB/Params) Pre-Segmentation DataSet (Sentences/Size/nWords)
AraBERTv0.2-base bert-base-arabertv02 543MB / 136M No 200M / 77GB / 8.6B
AraBERTv0.2-large bert-large-arabertv02 1.38G 371M No 200M / 77GB / 8.6B
AraBERTv2-base bert-base-arabertv2 543MB 136M Yes 200M / 77GB / 8.6B
AraBERTv2-large bert-large-arabertv2 1.38G 371M Yes 200M / 77GB / 8.6B
AraBERTv0.1-base bert-base-arabertv01 543MB 136M No 77M / 23GB / 2.7B
AraBERTv1-base bert-base-arabert 543MB 136M Yes 77M / 23GB / 2.7B

All models are available in the HuggingFace model page under the aubmindlab name. Checkpoints are available in PyTorch, TF2 and TF1 formats.

Better Pre-Processing and New Vocab

We identified an issue with AraBERTv1's wordpiece vocabulary. The issue came from punctuations and numbers that were still attached to words when learned the wordpiece vocab. We now insert a space between numbers and characters and around punctuation characters.

The new vocabulary was learnt using the BertWordpieceTokenizer from the tokenizers library, and should now support the Fast tokenizer implementation from the transformers library.

P.S.: All the old BERT codes should work with the new BERT, just change the model name and check the new preprocessing dunction Please read the section on how to use the preprocessing function

Bigger Dataset and More Compute

We used ~3.5 times more data, and trained for longer. For Dataset Sources see the Dataset Section

Model Hardware num of examples with seq len (128 / 512) 128 (Batch Size/ Num of Steps) 512 (Batch Size/ Num of Steps) Total Steps Total Time (in Days)
AraBERTv0.2-base TPUv3-8 420M / 207M 2560 / 1M 384/ 2M 3M -
AraBERTv0.2-large TPUv3-128 420M / 207M 13440 / 250K 2056 / 300K 550K 7
AraBERTv2-base TPUv3-8 420M / 207M 2560 / 1M 384/ 2M 3M -
AraBERTv2-large TPUv3-128 520M / 245M 13440 / 250K 2056 / 300K 550K 7
AraBERT-base (v1/v0.1) TPUv2-8 - 512 / 900K 128 / 300K 1.2M 4


The pretraining data used for the new AraBERT model is also used for Arabic GPT2 and ELECTRA.

The dataset consists of 77GB or 200,095,961 lines or 8,655,948,860 words or 82,232,988,358 chars (before applying Farasa Segmentation)

For the new dataset we added the unshuffled OSCAR corpus, after we thoroughly filter it, to the previous dataset used in AraBERTv1 but with out the websites that we previously crawled:


It is recommended to apply our preprocessing function before training/testing on any dataset. Install farasapy to segment text for AraBERT v1 & v2 pip install farasapy

from arabert.preprocess import ArabertPreprocessor

arabert_prep = ArabertPreprocessor(model_name=model_name)

text = "ولن نبالغ إذا قلنا إن هاتف أو كمبيوتر المكتب في زمننا هذا ضروري"



TensorFlow 1.x models

The TF1.x model are available in the HuggingFace models repo. You can download them as follows:

  • via git-lfs: clone all the models in a repo

    curl -s | sudo bash
    sudo apt-get install git-lfs
    git lfs install
    git clone
    tar -C ./MODEL_NAME -zxvf /content/MODEL_NAME/tf1_model.tar.gz

    where MODEL_NAME is any model under the aubmindlab name

  • via wget:

    • Go to the tf1_model.tar.gz file on
    • copy the oid sha256
    • then run wget (ex: for aragpt2-base: wget

If you used this model please cite us as :

Google Scholar has our Bibtex wrong (missing name), use this instead

  title={AraBERT: Transformer-based Model for Arabic Language Understanding},
  author={Antoun, Wissam and Baly, Fady and Hajj, Hazem},
  booktitle={LREC 2020 Workshop Language Resources and Evaluation Conference 11--16 May 2020},


Thanks to TensorFlow Research Cloud (TFRC) for the free access to Cloud TPUs, couldn't have done it without this program, and to the AUB MIND Lab Members for the continous support. Also thanks to Yakshof and Assafir for data and storage access. Another thanks for Habib Rahal (, for putting a face to AraBERT.


Wissam Antoun: Linkedin | Twitter | Github | |

Fady Baly: Linkedin | Twitter | Github | |

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