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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Can language models build genuine grounding through interaction? What explains language models' asymmetric difficulty with implicit versus explicit linguistic relations? Why don't LLMs reliably translate capability into accurate outputs? What compositional reasoning failures limit large language models despite scale? Do language models respond to social pressure and face-saving like humans? Do language models reason like humans or mimic surface patterns? What enables genuine semantic understanding in language models? How do multi-agent LLM systems fail distinctly compared to single agents? Why do LLM recommenders underperform collaborative filtering despite their capabilities?

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Original note title

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