Abstract
We propose a novel hybrid approach to lemmatization that enhances the seq2seq neural model with additional lemmas extracted from an external lexicon or a rule-based system. During training, the enhanced lemmatizer learns both to generate lemmas via a sequential decoder and copy the lemma characters from the external candidates supplied during run-time. Our lemmatizer enhanced with candidates extracted from the Apertium morphological analyzer achieves statistically significant improvements compared to baseline models not utilizing additional lemma information, achieves an average accuracy of 97.25% on a set of 23 UD languages, which is 0.55% higher than obtained with the Stanford Stanza model on the same set of languages. We also compare with other methods of integrating external data into lemmatization and show that our enhanced system performs considerably better than a simple lexicon extension method based on the Stanza system, and it achieves complementary improvements w.r.t. the data augmentation method.- Anthology ID:
- 2021.eacl-main.272
- Volume:
- Proceedings of the 16th Conference of the European Chapter of the Association for Computational Linguistics: Main Volume
- Month:
- April
- Year:
- 2021
- Address:
- Online
- Venue:
- EACL
- SIG:
- Publisher:
- Association for Computational Linguistics
- Note:
- Pages:
- 3112–3122
- Language:
- URL:
- https://aclanthology.org/2021.eacl-main.272
- DOI:
- 10.18653/v1/2021.eacl-main.272
- Cite (ACL):
- Kirill Milintsevich and Kairit Sirts. 2021. Enhancing Sequence-to-Sequence Neural Lemmatization with External Resources. In Proceedings of the 16th Conference of the European Chapter of the Association for Computational Linguistics: Main Volume, pages 3112–3122, Online. Association for Computational Linguistics.
- Cite (Informal):
- Enhancing Sequence-to-Sequence Neural Lemmatization with External Resources (Milintsevich & Sirts, EACL 2021)
- PDF:
- https://preview.aclanthology.org/auto-file-uploads/2021.eacl-main.272.pdf
- Code
- 501Good/lexicon-enhanced-lemmatization