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Preserving Comorian Linguistic Heritage: Bidirectional Transliteration Between the Latin Alphabet and the Kamar-Eddine System

Paper · 2025 · Abdou Mohamed Naira, Abdessalam Bahafid, Zakarya Erraji et al.

Summary

Comorian (ShiKomori) is now mostly written in Latin letters. An older Arabic-based orthography, the Kamar-Eddine system from the 1960s, is still the only script some elderly speakers read, and many archival manuscripts use it. No NLP work had addressed it. The authors first collect the system's rules. Kamar-Eddine replaced diacritics with long-vowel letters, used the shadda to mark affricates, and kept letters borrowed from Persian. From these rules they build Shialifube, a rule-based tool that converts text in both directions. It detects the input script, loads the matching correspondence dictionary, and handles digraphs before single letters. No parallel Latin–Arabic corpus exists, so they evaluate by sending Latin text to Arabic and back and comparing the result with the original. After four rounds of refinement this gives 14.84% WER and 9.56% CER. They also fine-tune Whisper on transliterated data, producing the first Comorian ASR model in Arabic script. Its accuracy comes close to the Latin-script model's. The work matters because it opens a low-resource heritage script to digitization and NLP.

Key points

  • Shialifube is released as a PyPI library, with code on GitHub and a HuggingFace Space. The four dialects (ShiNgazidja, ShiMwali, ShiNdzuani, ShiMaore) are treated as one language, partly because data is scarce and partly because the Kamar-Eddine rules make no dialect distinctions.
  • Round-trip WER/CER across the four iterations:
    • no digraph handling: 68.56/34.41
    • adding digraphs and long vowels: 43.09/21.30
    • standardizing the corpus: 33.89/16.75
    • handling remaining edge cases: 14.84/9.56
  • In the Kamar-Eddine system, /e/ and /o/ get dedicated long-vowel letters. This removes ambiguities such as mezi "month" vs mizi "roots", which earlier adaptations wrote identically.
  • Whisper fine-tuning results:
    • Latin script, with Swahili as the language setting: WER 35.48%, CER 17.76%.
    • Arabic script, with Arabic as the language setting: WER 37.44%, CER 21.42%.
  • The authors give two reasons for the Arabic-script gap: the transliterated (not hand-annotated) training data is noisier, and the pretrained model's vocabulary produces more unknown tokens for that script.
  • The motivation comes partly from Maltese, where rewriting text in Arabic characters improved NLP task scores.

Interesting ideas

  • I1. Each output comes with a confidence score computed by inverting it and measuring how much of the original survives. This gives a cheap self-check when no gold data exists.
  • I2. The authors judge a data transformation by training a downstream model on the transformed data and comparing it to a model trained on the original. If the conversion damaged the data, the downstream score would drop.
  • I3. The error rate is logged after each batch of rule changes (digraphs, then normalization, then edge cases). This makes each rule family's contribution visible and explainable.
  • I4. Multi-character units are matched and replaced before single characters, which prevents greedy mis-segmentation.
  • I5. Simple rules detect the input type first and route it to the right resource, instead of using one model for every case.

For Mova

How these ideas could serve Mova, our small open language model — its files, stages and tests:

  • I1 (back): The text → graph → text compressor could report a per-sentence round-trip WER as a confidence signal, flagging graphs that lose information.
  • I2 (tree): When converting treebanks between UD dialects, train the perceptron parser on converted and unconverted versions and compare LAS, to catch conversion rules that corrupt structure.
  • I3 (learn): Self-induced repair rules could be added in tracked batches, each with its own before/after metric, so a rule that helps nothing can be identified and dropped.
  • I4 (tokens): The en tokenizer could apply the same longest-match-first ordering to multiword expressions and contractions before splitting.
  • I5 (tokens): A lightweight rule-based detector for genre or text register could pick specialized lexicons before tagging, keeping the routing decision explainable.

Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.

 Institutions

Cite

Cite as Abdou Mohamed Naira, Abdessalam Bahafid, Zakarya Erraji, Anass Allak, Mohamed Soibira Naoufal and Imade Benelallam. 2025. Preserving Comorian Linguistic Heritage: Bidirectional Transliteration Between the Latin Alphabet and the Kamar-Eddine System. Proceedings of the 9th Joint SIGHUM Workshop on Computational Linguistics for Cultural Heritage, Social Sciences, Humanities and Literature (LaTeCH-CLfL 2025).

The paper itself, not this page. BibTeX from the library's record of the work. DOI 10.18653/v1/2025.latechclfl-1.2

@inproceedings{naira2025preserving,
  title = {{Preserving Comorian Linguistic Heritage: Bidirectional Transliteration Between the Latin Alphabet and the Kamar-Eddine System}},
  author = {Abdou Mohamed Naira, Abdessalam Bahafid, Zakarya Erraji, Anass Allak, Mohamed Soibira Naoufal and Imade Benelallam},
  booktitle = {Proceedings of the 9th Joint SIGHUM Workshop on Computational Linguistics for Cultural Heritage, Social Sciences, Humanities and Literature (LaTeCH-CLfL 2025)},
  year = {2025},
  doi = {10.18653/v1/2025.latechclfl-1.2},
  url = {https://doi.org/10.18653/v1/2025.latechclfl-1.2}
}

References

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