Right Tool, Right Job: Native-Language Evaluation, Tokenizer Sensitivity, and Methodological Findings from a French-Only BabyLM

Adam Zachary Wasserman, David Beauchemin


Abstract
We submit MÉTRON-FR, a 125M GPT-2 pretrained on 92.50M words of French, to the BabyLM 2026 Strict track. It scores 85.97 ± 0.17% on QFrBLiMP and 62.80% on the BabyLM-weighted leaderboard. A cross-lingual GLUE protocol that combines French task-data translation with rank-16 LoRA produces a sharp task-type gradient: relational tasks gain measurably, while world-knowledge tasks regress. Bilingual Lexicon Induction aligns the French embeddings to GPT-2 at p@1 = 68.84 ± 8.61%, 32× above chance, suggesting cross-lingual alignment tracks acquired grammatical competence rather than training duration. An ablation study shows that single-token zero-shot scoring is dominated by tokenizer and template artifacts at the child scale, motivating tokenizer-swap sensitivity, placebo-controlled prompting, and native-language minimal-pair benchmarks as standard diagnostics.
Anthology ID:
2026.babylm-main.30
Volume:
Proceedings of the Second BabyLM Workshop
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Leshem Choshen, Ryan Cotterell, Mustafa Omer Gul, Jaap Jumelet, Tal Linzen, Aaron Mueller, Suchir Salhan, Raj Sanjay Shah, Alex Warstadt, Ethan Gotlieb Wilcox
Venues:
BabyLM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
369–387
Language:
URL:
https://aclanthology.org/2026.babylm-main.30/
DOI:
Bibkey:
Cite (ACL):
Adam Zachary Wasserman and David Beauchemin. 2026. Right Tool, Right Job: Native-Language Evaluation, Tokenizer Sensitivity, and Methodological Findings from a French-Only BabyLM. In Proceedings of the Second BabyLM Workshop, pages 369–387, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Right Tool, Right Job: Native-Language Evaluation, Tokenizer Sensitivity, and Methodological Findings from a French-Only BabyLM (Wasserman & Beauchemin, BabyLM 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.babylm-main.30.pdf