Subword-Based Comparative Linguistics across 242 Languages Using Wikipedia Glottosets

Iaroslav Chelombitko, Mika Hämäläinen, Aleksey Komissarov


Abstract
We release **morphoBPE**, a framework for training and comparing per-language BPE tokenizers across 242 Latin- and Cyrillic-script languages built from Wikipedia *glottosets* (per-language TF-DF lexicons), with four diagnostic evaluations of what BPE captures across scripts. Unsupervised language identification by token count reaches 13.8% accuracy across 320 Latin-script languages, against 19.83% for supervised fastText ‘lid.176‘, which returns zero for 147 of them because they fall outside its 176-language alphabet, including our best performers (Lak 81.5%, Cree 80.6%, Inuktitut 63.8%, Kabardian 60.1%). BPE aligns with morpheme boundaries at F1 = 0.28 across 15 languages (Morfessor: 0.43), and beats supervised character-*n*-gram cross-lingual transfer by +37% F1 across six pairs where labeled morphology is unavailable. BPE distance correlates moderately with Glottolog phylogeny (Mantel r = 0.329). We position per-language BPE as a coverage-first diagnostic for languages outside the supervised long tail, not as a substitute for supervised methods where labels exist.
Anthology ID:
2026.mrl-1.4
Volume:
Proceedings of the 6th Workshop on Multilingual Representation Learning (MRL 2026)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
David Ifeoluwa Adelani, Jesujoba Alabi, Catherine Arnett, Tyler Chang, C.M. Downey, Omer Goldman, Senyu Li, Lester James Validad Miranda, Jirui Qi, David Stap, Genta Indra Winata, Xinyu Crystina Zhang
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MRL | WS
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Publisher:
Association for Computational Linguistics
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Pages:
37–52
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URL:
https://aclanthology.org/2026.mrl-1.4/
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Cite (ACL):
Iaroslav Chelombitko, Mika Hämäläinen, and Aleksey Komissarov. 2026. Subword-Based Comparative Linguistics across 242 Languages Using Wikipedia Glottosets. In Proceedings of the 6th Workshop on Multilingual Representation Learning (MRL 2026), pages 37–52, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Subword-Based Comparative Linguistics across 242 Languages Using Wikipedia Glottosets (Chelombitko et al., MRL 2026)
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https://aclanthology.org/2026.mrl-1.4.pdf