Orthographic Constraint Satisfaction and Human Difficulty Alignment in Large Language Models

Bryan E. Tuck, Rakesh Verma


Abstract
Large language models must satisfy hard orthographic constraints during controlled text generation, yet systematic cross-family evaluation remains limited. We evaluate 39 configurations spanning three model families (Qwen3, Claude Haiku 4.5, GPT-5-mini) on 58 word puzzles requiring character-level constraint satisfaction. Cross-family differences produce substantially larger performance gaps (2.0–2.2×, F1 = 0.761 vs. 0.343) than parameter scaling within families (83% gain from 4B to 32B scaling), and a partial-correlation analysis rules out tokenizer design as a confound for within-family scaling. Thinking budget sensitivity proves heterogeneous: high-capacity models show strong returns (+0.102 to +0.136 F1), while mid-sized variants saturate or degrade, showing inconsistent compute benefits. Using difficulty ratings from 10,000 human solvers per puzzle, we establish modest but consistent calibration (ρ = 0.28–0.42) across all families, yet identify systematic failures on common words with unusual orthography (“data”, “loll”, “acai”: 83–91% human success, 94–98% model miss rate). These failures point to over-reliance on distributional plausibility that penalizes orthographically atypical but constraint-valid patterns.
Anthology ID:
2026.lrec-1.426
Volume:
Proceedings of the Fifteenth Language Resources and Evaluation Conference
Month:
May
Year:
2026
Address:
Palma de Mallorca, Spain
Editors:
Stelios Piperidis, Núria Bel, Henk van den Heuvel, Nancy Ide, Simon Krek, Antonio Toral
Venue:
LREC
SIG:
Publisher:
ELRA Language Resource Association
Note:
Pages:
5466–5481
Language:
External URL:
https://lrec.elra.info/lrec2026-main-426
DOI:
10.63317/3erhoom72odv
Bibkey:
Cite (ACL):
Bryan E. Tuck and Rakesh Verma. 2026. Orthographic Constraint Satisfaction and Human Difficulty Alignment in Large Language Models. In Proceedings of the Fifteenth Language Resources and Evaluation Conference, pages 5466–5481, Palma de Mallorca, Spain. ELRA Language Resource Association.
Cite (Informal):
Orthographic Constraint Satisfaction and Human Difficulty Alignment in Large Language Models (Tuck & Verma, LREC 2026)
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