Neural Coreference Resolution for Arabic
Summary
Arabic coreference resolution has barely advanced since the CoNLL 2012 shared task. The strongest system was still the feature-based resolver of Björkelund and Kuhn (2014), and no neural model had been tried. The authors fill this gap by adapting a leading English end-to-end architecture to Arabic. Their baseline is the Lee et al. (2018) model with BERT embeddings instead of ELMo, trained and tested on the Arabic part of OntoNotes 5.0 (CoNLL 2012 data). They add three improvements on top of it:
- rule-based normalization of letter variants and removal of diacritics;
- the monolingual AraBERT in place of multilingual BERT;
- a separately trained mention detector, combined with an "end-to-end annealing" schedule that mixes joint and pipeline training.
The complete system reaches 63.9% CoNLL F1, which is 15.2 points above the previous best. This is the first neural resolver built specifically for Arabic, and its code is public. It shows that modern architectures work even with a small training corpus. The remaining obstacles are scarce annotated data and the lack of an Arabic BERT-large.
Key points
- Code is released at github.com/juntaoy/aracoref. The model builds on Lee et al. (2018) with BERT embeddings in the style of Kantor and Globerson (2019a), plus fastText and character CNN features.
- Normalization and diacritic stripping alone add about 7 CoNLL F1 points, mainly by raising recall through reduced sparsity.
- Replacing multilingual BERT with AraBERT adds roughly 4.7–4.8 points for coreference and 2.4 points for mention detection.
- The external mention detector with end-to-end annealing adds 0.8 points and raises mention recall by 2.3 points. The final score is 63.9% CoNLL F1, which is +15.2 over Björkelund and Kuhn (2014).
- The Arabic portion of OntoNotes is small: about 300,000 tokens in 447 documents. ACE has about 500,000 Arabic tokens but covers only seven entity types.
Cited by
- Coreference Resolution through a seq2seq Transition-Based System
- Exploring Pre-Trained Transformers and Bilingual Transfer Learning for Arabic Coreference Resolution
- Multilingual Coreference Resolution in Low-resource South Asian Languages
Cite
@inproceedings{aloraini2020neural,
title = {{Neural Coreference Resolution for Arabic}},
author = {Aloraini, Abdulrahman and Yu, Juntao and Poesio, Massimo},
booktitle = {Proceedings of the Third Workshop on Computational Models of Reference, Anaphora and Coreference},
year = {2020},
eprint = {2011.00286},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2011.00286}
}References
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