Thinking While Speaking: Inference-Time Knowledge Transfer for Responsive and Intelligent Conversational Voice Agents

Vidya Srinivas, Zachary Englhardt, Vikram Iyer, Shwetak Patel


Abstract
Voice agents face a fundamental tension: the reasoning, retrieval, and tool use that make foundation models capable are iterative and slow, while conversational interaction demands prompt responses. Smaller, real-time models meet the latency bar but do not match foundation models on complex tasks, leaving current voice agents to trade off responsiveness and capability. We introduce conversational infill, where a small Talker model both fluently integrates streamed Reasoner model knowledge into its responses during inference and immediately generates contextually grounded responses to hide external Reasoner latency. We curate a 290,571-example dataset and demonstrate that this task is learnable across seven small language models (135M to 1.7B parameters).

Our system, ConvFill, runs on an Apple M2 with millisecond-level latency, while remaining within 6.3% of corresponding frontier Reasoner performance. Conversational infill unlocks a new point on the latency–capability Pareto frontier, offering a practical path toward responsive and capable voice agents.
Anthology ID:
2026.findings-emnlp.1371
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
29148–29187
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1371/
DOI:
10.18653/2026.findings-emnlp.1371
Bibkey:
Cite (ACL):
Vidya Srinivas, Zachary Englhardt, Vikram Iyer, and Shwetak Patel. 2026. Thinking While Speaking: Inference-Time Knowledge Transfer for Responsive and Intelligent Conversational Voice Agents. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 29148–29187, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Thinking While Speaking: Inference-Time Knowledge Transfer for Responsive and Intelligent Conversational Voice Agents (Srinivas et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.1371.pdf