To “Ba” or Not to “Ba”? LLM Surprisal as a Diagnostic of Context-Sensitive Language Understanding in L2 Chinese

Shengjie Zhang, Yan Cong


Abstract
Some difficulties in learning Chinese as a second language (L2 Chinese) involve choosing a sentence pattern that is grammatically well formed but less natural in context. Mandarin ba/SVO choice is one such case: learners may avoid ba when the discourse favors it or extend it to contexts where SVO is more appropriate. Because edit-based correction systems may leave both alternatives unchanged, diagnosing these choices requires sensitivity to discourse context, making the task a targeted test of context-sensitive natural language understanding (NLU). Using 200 controlled discourse contexts, we examine whether autoregressive LLM surprisal can serve as a graded diagnostic of this distinction. Across 21 open-weight models, sentence-level mean surprisal identifies the contextually preferred continuation with a mean model-level accuracy of 87.93%, whereas a MacBERT-based correction baseline leaves most contextually non-preferred continuations unchanged. Relevant context generally lowers surprisal for the intended continuation, and sentence-level scoring is more reliable than first-token scoring, whose interpretation varies with tokenizer granularity. The results suggest that surprisal can complement edit-based correction in L2 pragmatic assessment, while cross-model asymmetries, structural preference biases, and tokenizer effects underscore the need for construction-specific controls and human interpretation when evaluating context-sensitive NLU.
Anthology ID:
2026.luhme-1.18
Volume:
Proceedings of the 3rd Workshop on Language Understanding in the Human-Machine Era (LUHME 2026)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Rui Sousa-Silva, Henrique Lopes Cardoso, Maarit Koponen, Antonio Pareja-Lora
Venues:
LUHME | WS
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Publisher:
Association for Computational Linguistics
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Pages:
227–245
Language:
URL:
https://aclanthology.org/2026.luhme-1.18/
DOI:
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Cite (ACL):
Shengjie Zhang and Yan Cong. 2026. To “Ba” or Not to “Ba”? LLM Surprisal as a Diagnostic of Context-Sensitive Language Understanding in L2 Chinese. In Proceedings of the 3rd Workshop on Language Understanding in the Human-Machine Era (LUHME 2026), pages 227–245, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
To “Ba” or Not to “Ba”? LLM Surprisal as a Diagnostic of Context-Sensitive Language Understanding in L2 Chinese (Zhang & Cong, LUHME 2026)
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PDF:
https://aclanthology.org/2026.luhme-1.18.pdf