Igbo Diacritic Restoration using Embedding Models

Ignatius Ezeani, Mark Hepple, Ikechukwu Onyenwe, Enemouh Chioma


Abstract
Igbo is a low-resource language spoken by approximately 30 million people worldwide. It is the native language of the Igbo people of south-eastern Nigeria. In Igbo language, diacritics - orthographic and tonal - play a huge role in the distinguishing the meaning and pronunciation of words. Omitting diacritics in texts often leads to lexical ambiguity. Diacritic restoration is a pre-processing task that replaces missing diacritics on words from which they have been removed. In this work, we applied embedding models to the diacritic restoration task and compared their performances to those of n-gram models. Although word embedding models have been successfully applied to various NLP tasks, it has not been used, to our knowledge, for diacritic restoration. Two classes of word embeddings models were used: those projected from the English embedding space; and those trained with Igbo bible corpus (≈ 1m). Our best result, 82.49%, is an improvement on the baseline n-gram models.
Anthology ID:
N18-4008
Volume:
Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Student Research Workshop
Month:
June
Year:
2018
Address:
New Orleans, Louisiana, USA
Editors:
Silvio Ricardo Cordeiro, Shereen Oraby, Umashanthi Pavalanathan, Kyeongmin Rim
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
54–60
Language:
URL:
https://aclanthology.org/N18-4008
DOI:
10.18653/v1/N18-4008
Bibkey:
Cite (ACL):
Ignatius Ezeani, Mark Hepple, Ikechukwu Onyenwe, and Enemouh Chioma. 2018. Igbo Diacritic Restoration using Embedding Models. In Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Student Research Workshop, pages 54–60, New Orleans, Louisiana, USA. Association for Computational Linguistics.
Cite (Informal):
Igbo Diacritic Restoration using Embedding Models (Ezeani et al., NAACL 2018)
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PDF:
https://aclanthology.org/N18-4008.pdf
Video:
 https://aclanthology.org/N18-4008.mp4