SYNTHESIS NOTE
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Why do language models fail at communicative optimization?

LLMs excel at learning surface statistical patterns from text but struggle with deeper principles of how language achieves efficient communication. What distinguishes these two types of linguistic knowledge?

Synthesis note · 2026-02-21 · sourced from Linguistics, NLP, NLU

"Do Large Language Models Resemble Humans in Language Use?" (Yiu et al. 2023) evaluates LLMs on a wide range of human linguistic regularities — not just grammaticality but psycholinguistic phenomena. The results show a consistent pattern of success and failure that tracks a specific distinction.

LLMs succeed on:

These regularities are learnable from distributional patterns in text — they appear consistently across large corpora and can be acquired through form-to-form prediction.

LLMs fail on:

These regularities require something beyond distributional pattern matching. They involve principles of why language works for communication — efficiency under communicative pressure, contextual interpretation that goes beyond local statistics, integration across discourse.

The discriminating principle: statistical regularities that appear as consistent patterns in training data transfer. Regularities that emerge from communicative optimization — the pragmatic logic of why language has the forms it does — do not transfer, because they are not present in surface form as trainable signals.

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Do language models learn underlying linguistic structure or merely surface patterns? What explains the gap between LLM semantic understanding and production? Why doesn't LLM knowledge translate to improved reasoning outputs? Do language models truly understand their encoded knowledge or merely retrieve patterns? Can language models develop genuine communicative grounding with humans? What distinguishes genuine understanding from correct linguistic performance? How do standardized artifacts improve coordination in multi-agent systems? How does explicit structure improve LLM reasoning on complex tasks? Do language models genuinely understand or primarily match statistical patterns?

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Original note title

llms replicate local statistical regularities in language but fail to acquire communicative optimization principles