Tokenization and Morphology in Multilingual Language Models: A Comparative Analysis of mT5 and ByT5
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Abstract (arXiv)
Morphology is a crucial factor for multilingual language modeling as it poses direct challenges for tokenization. Here, we seek to understand how tokenization influences the morphological knowledge encoded in multilingual language models. Specifically, we capture the impact of tokenization by contrasting two multilingual language models: mT5 and ByT5. The two models share the same architecture, training objective, and training data and only differ in their tokenization strategies: subword tokenization vs.@ character-level tokenization. Probing the morphological knowledge encoded in these models on four tasks and 17 languages, our analyses show that the models learn the morphological systems of some languages better than others and that morphological information is encoded in the middle and late layers. Finally, we show that languages with more irregularities benefit more from having a higher share of the pre-training data.
Key facts. Cited by 14 papers in the map (data through 14 Oct 2026). Builds on 50 of its 79 references that are in the map. First posted on arXiv 15 Oct 2024.
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- 2026The Script Tax: Measuring Tokenization-Driven Efficiency and Latency Disparities in Multilingual Language Models19 Jan 2026
- 2026The Roots of Performance Disparity in Multilingual Language Models: Intrinsic Modeling Difficulty or Design Choices?12 Jan 2026
- 2025TokSuite: Measuring the Impact of Tokenizer Choice on Language Model Behavior23 Dec 2025
- 2025FastPOS: Language-Agnostic Scalable POS Tagging Framework Low-Resource Use Case30 Nov 2025
- 2025Orthographic Constraint Satisfaction and Human Difficulty Alignment in Large Language Models26 Nov 2025
- 2025MUTANT: A Recipe for Multilingual Tokenizer Design5 Nov 2025
- 2025Community size rather than grammatical complexity better predicts Large Language Model accuracy in a novel Wug Test14 Oct 2025
- 2025UNVEILING: What Makes Linguistics Olympiad Puzzles Tricky for LLMs?15 Aug 2025
- 2026The Roots of Performance Disparity in Multilingual Language Models: Intrinsic Modeling Difficulty or Design Choices?cited by 11
- 2025Model Internal Sleuthing: Finding Lexical Identity and Inflectional Features in Modern Language Modelscited by 5
- 2025MUTANT: A Recipe for Multilingual Tokenizer Designcited by 4
- 2025TokSuite: Measuring the Impact of Tokenizer Choice on Language Model Behaviorcited by 4
- 2026The Script Tax: Measuring Tokenization-Driven Efficiency and Latency Disparities in Multilingual Language Modelscited by 4
- 2025Community size rather than grammatical complexity better predicts Large Language Model accuracy in a novel Wug Testcited by 2
- 2026Modelling the Morphology of Verbal Paradigms: A Case Study in the Tokenization of Turkish and Hebrewcited by 2
- 2025Orthographic Constraint Satisfaction and Human Difficulty Alignment in Large Language Modelscited by 0
- 2025FastPOS: Language-Agnostic Scalable POS Tagging Framework Low-Resource Use Casecited by 0
- 2026Lost in the Tower of Babel: The Adverse Effects of Incidental Multilingualism in LLMscited by 0
- 2026When Tokenization is Secretly Output Supervisioncited by 0
- 2026The Limits of BPE Tokenization in Polish: Segmentation-Flexional Forms, Grammatical Anchoring, and First-Person Stability in Inflectional Language Modelscited by 0
- 2026When Tokenization is Secretly Output Supervision1 Sep 2026
- 2026The Limits of BPE Tokenization in Polish: Segmentation-Flexional Forms, Grammatical Anchoring, and First-Person Stability in Inflectional Language Models17 Jul 2026
- 2026Lost in the Tower of Babel: The Adverse Effects of Incidental Multilingualism in LLMs2 May 2026
- 2026Modelling the Morphology of Verbal Paradigms: A Case Study in the Tokenization of Turkish and Hebrew5 Feb 2026
- 2026The Script Tax: Measuring Tokenization-Driven Efficiency and Latency Disparities in Multilingual Language Models19 Jan 2026
- 2026The Roots of Performance Disparity in Multilingual Language Models: Intrinsic Modeling Difficulty or Design Choices?12 Jan 2026
- 2025TokSuite: Measuring the Impact of Tokenizer Choice on Language Model Behavior23 Dec 2025
- 2025FastPOS: Language-Agnostic Scalable POS Tagging Framework Low-Resource Use Case30 Nov 2025
- 2025Orthographic Constraint Satisfaction and Human Difficulty Alignment in Large Language Models26 Nov 2025
- 2025MUTANT: A Recipe for Multilingual Tokenizer Design5 Nov 2025
- 2025Community size rather than grammatical complexity better predicts Large Language Model accuracy in a novel Wug Test14 Oct 2025
- 2025Model Internal Sleuthing: Finding Lexical Identity and Inflectional Features in Modern Language Models2 Jun 2025