BabyConceptLM: Exploring Dynamic Concept Computation under Restricted Language Exposure

Yizhe Xu, Ming Song, Danni He, Jianghao Liu, Yitong Wang, Qing Cai


Abstract
Human language learning takes place under limited exposure and is shaped by structured regularities in the input, whereas standard Transformers apply a largely uniform sequence of computations at every token position. We ask whether dynamic latent segmentation can provide a useful inductive bias for language modeling under BabyLM-scale data constraints. BabyConceptLM causally encodes tokens, groups contextual states into learned contiguous latent segments, processes the shorter sequence with a deeper latent-level backbone, and returns to token resolution through a leakage-safe causal readout. We evaluate two profiles using recipe-matched token-only controls, with analyses of computational cost and segmentation behavior. Across English, multilingual, and Chinese comparisons, BabyConceptLM trails matched token-only controls by 0.60–1.47 points. Estimated padding-aware dense-forward FLOPs are reduced by 26% and 39% for the English and multilingual 5/8/3 models, respectively, but increase for the Chinese 2/4/2 configuration. Segmentation audits show weak alignment with word boundaries and predominantly length-driven behavior, with the larger model frequently reaching its eight-token segment cap. These results show that latent segmentation can yield a favorable compute–accuracy trade-off in some configurations, but does not by itself produce linguistically structured units or improved predictive performance. BabyConceptLM serves as a diagnostic test of hierarchical latent computation under restricted language exposure.
Anthology ID:
2026.babylm-main.61
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:
779–804
Language:
URL:
https://aclanthology.org/2026.babylm-main.61/
DOI:
Bibkey:
Cite (ACL):
Yizhe Xu, Ming Song, Danni He, Jianghao Liu, Yitong Wang, and Qing Cai. 2026. BabyConceptLM: Exploring Dynamic Concept Computation under Restricted Language Exposure. In Proceedings of the Second BabyLM Workshop, pages 779–804, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
BabyConceptLM: Exploring Dynamic Concept Computation under Restricted Language Exposure (Xu et al., BabyLM 2026)
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PDF:
https://aclanthology.org/2026.babylm-main.61.pdf