Grammar Control in Dialogue Response Generation for Language Learning Chatbots

Dominik Glandorf, Peng Cui, Detmar Meurers, Mrinmaya Sachan


Abstract
Chatbots based on large language models offer cheap conversation practice opportunities for language learners. However, they are hard to control for linguistic forms that correspond to learners’ current needs, such as grammar. We control grammar in chatbot conversation practice by grounding a dialogue response generation model in a pedagogical repository of grammar skills. We also explore how this control helps learners to produce specific grammar. We comprehensively evaluate prompting, fine-tuning, and decoding strategies for grammar-controlled dialogue response generation. Strategically decoding Llama3 outperforms GPT-3.5 when tolerating minor response quality losses. Our simulation predicts grammar-controlled responses to support grammar acquisition adapted to learner proficiency. Existing language learning chatbots and research on second language acquisition benefit from these affordances. Code available on GitHub.
Anthology ID:
2025.naacl-long.495
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
9820–9839
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.495/
DOI:
Bibkey:
Cite (ACL):
Dominik Glandorf, Peng Cui, Detmar Meurers, and Mrinmaya Sachan. 2025. Grammar Control in Dialogue Response Generation for Language Learning Chatbots. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers), pages 9820–9839, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
Grammar Control in Dialogue Response Generation for Language Learning Chatbots (Glandorf et al., NAACL 2025)
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PDF:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.495.pdf