CoSy: Conversational Synthesis for Grounded Question Answering

Patrick Huber, Arash Einolghozati, Rylan Conway, Kanika Narang, Matt Smith, Waqar Nayyar, Adithya Sagar, Ahmed A Aly, Akshat Shrivastava


Abstract
High-quality, large-scale conversational datasets are scarce, making it difficult to train on-device language models (~1B parameters) as effective assistants. We introduce CoSy (Conversational Synthesis), a novel framework for generating diverse, steerable, multi-turn conversations at scale. CoSY combines three key mechanisms: (1) conversational graphs that ensure natural dialogue flow, (2) turn-based prompt augmentations for diversity, and (3) explicit linguistic phenomena for coherence. We evaluate CoSy on conversational grounded reasoning tasks (i.e. answering questions based on contextual information), a core on-device use case.Our on-device sized models trained on CoSy-synthesized data achieve competitive performance with human-annotated baselines and outperform instruction-tuned models of up to 70B parameters in zero-shot settings.
Anthology ID:
2026.gem-main.2
Volume:
Proceedings of the Fifth Workshop on Generation, Evaluation and Metrics (GEM)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Simon Mille, Sebastian Gehrmann, Patrícia Schmidtová, Ondřej Dušek, Marzieh Fadaee, Kyle Lo, Enrico Santus, Gabriel Stanovsky
Venues:
GEM | WS
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Publisher:
Association for Computational Linguistics
Note:
Pages:
1–10
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.gem-main.2/
DOI:
Bibkey:
Cite (ACL):
Patrick Huber, Arash Einolghozati, Rylan Conway, Kanika Narang, Matt Smith, Waqar Nayyar, Adithya Sagar, Ahmed A Aly, and Akshat Shrivastava. 2026. CoSy: Conversational Synthesis for Grounded Question Answering. In Proceedings of the Fifth Workshop on Generation, Evaluation and Metrics (GEM), pages 1–10, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
CoSy: Conversational Synthesis for Grounded Question Answering (Huber et al., GEM 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.gem-main.2.pdf