Corpus-Based Diacritic Restoration for South Slavic Languages

Nikola Ljubešić, Tomaž Erjavec, Darja Fišer


Abstract
In computer-mediated communication, Latin-based scripts users often omit diacritics when writing. Such text is typically easily understandable to humans but very difficult for computational processing because many words become ambiguous or unknown. Letter-level approaches to diacritic restoration generalise better and do not require a lot of training data but word-level approaches tend to yield better results. However, they typically rely on a lexicon which is an expensive resource, not covering non-standard forms, and often not available for less-resourced languages. In this paper we present diacritic restoration models that are trained on easy-to-acquire corpora. We test three different types of corpora (Wikipedia, general web, Twitter) for three South Slavic languages (Croatian, Serbian and Slovene) and evaluate them on two types of text: standard (Wikipedia) and non-standard (Twitter). The proposed approach considerably outperforms charlifter, so far the only open source tool available for this task. We make the best performing systems freely available.
Anthology ID:
L16-1573
Volume:
Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16)
Month:
May
Year:
2016
Address:
Portorož, Slovenia
Venue:
LREC
SIG:
Publisher:
European Language Resources Association (ELRA)
Note:
Pages:
3612–3616
Language:
URL:
https://aclanthology.org/L16-1573
DOI:
Bibkey:
Cite (ACL):
Nikola Ljubešić, Tomaž Erjavec, and Darja Fišer. 2016. Corpus-Based Diacritic Restoration for South Slavic Languages. In Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16), pages 3612–3616, Portorož, Slovenia. European Language Resources Association (ELRA).
Cite (Informal):
Corpus-Based Diacritic Restoration for South Slavic Languages (Ljubešić et al., LREC 2016)
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PDF:
https://preview.aclanthology.org/paclic-22-ingestion/L16-1573.pdf