Improving Latin Dependency Parsing by Combining Treebanks and Predictions

Hanna-Mari Kristiina Kupari, Erik Henriksson, Veronika Laippala, Jenna Kanerva


Abstract
This paper introduces new models designed to improve the morpho-syntactic parsing of the five largest Latin treebanks in the Universal Dependencies (UD) framework. First, using two state-of-the-art parsers, Trankit and Stanza, along with our custom UD tagger, we train new models on the five treebanks both individually and by combining them into novel merged datasets. We also test the models on the CIRCSE test set. In an additional experiment, we evaluate whether this set can be accurately tagged using the novel LASLA corpus (https://github.com/CIRCSE/LASLA). Second, we aim to improve the results by combining the predictions of different models through an atomic morphological feature voting system. The results of our two main experiments demonstrate significant improvements, particularly for the smaller treebanks, with LAS scores increasing by 16.10 and 11.85%-points for UDante and Perseus, respectively (Gamba and Zeman, 2023a). Additionally, the voting system for morphological features (FEATS) brings improvements, especially for the smaller Latin treebanks: Perseus 3.15% and CIRCSE 2.47%-points. Tagging the CIRCSE set with our custom model using the LASLA model improves POS 6.71 and FEATS 11.04%-points respectively, compared to our best-performing UD PROIEL model. Our results show that larger datasets and ensemble predictions can significantly improve performance.
Anthology ID:
2024.nlp4dh-1.21
Volume:
Proceedings of the 4th International Conference on Natural Language Processing for Digital Humanities
Month:
November
Year:
2024
Address:
Miami, USA
Editors:
Mika Hämäläinen, Emily Öhman, So Miyagawa, Khalid Alnajjar, Yuri Bizzoni
Venue:
NLP4DH
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
216–228
Language:
URL:
https://aclanthology.org/2024.nlp4dh-1.21
DOI:
Bibkey:
Cite (ACL):
Hanna-Mari Kristiina Kupari, Erik Henriksson, Veronika Laippala, and Jenna Kanerva. 2024. Improving Latin Dependency Parsing by Combining Treebanks and Predictions. In Proceedings of the 4th International Conference on Natural Language Processing for Digital Humanities, pages 216–228, Miami, USA. Association for Computational Linguistics.
Cite (Informal):
Improving Latin Dependency Parsing by Combining Treebanks and Predictions (Kupari et al., NLP4DH 2024)
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PDF:
https://aclanthology.org/2024.nlp4dh-1.21.pdf