arXiv Computation and Language

Prompts versus Rules: Auditing and Controlling Speech Naturalness Behaviors in Voice User Simulators

The paper evaluates how well voice user simulators generate realistic speech naturalness behaviors such as disfluency, interruption, and backchanneling. By auditing the tau-Voice LLM-based prompting approach and a rule-based injection algorithm, the authors find that prompting is unreliable and produces inconsistent, less natural speech, whereas the rule-based method yields controllable and diverse behaviors that better align with natural speech patterns. The study highlights the need for linguistically informed deterministic or specialized models and stresses the importance of auditing realized behaviors rather than relying solely on configured settings.

Hugging Face Trending Papers
Sep 3

Scalable Context Orchestration for Serving LLMs Over Voice

Scalable Context Orchestration for Serving LLMs Over Voice presents llmovoice, a middleware that explicitly models voice context—including speaking rate, background noise, and packet loss—to guide large language model responses. By constructing a bounded voice context at each turn, llmovoice improves alignment with user preferences and reduces errors, achieving a 52.4% drop in speaking‑rate alignment error and a 0.9% false‑interruption rate under packet loss. In addition, it cuts model usage costs dramatically, lowering per‑turn cost by up to 24.9× while maintaining 98.7% of baseline answer quality in long sessions.

arXiv AI
Sep 7

Scalable Context Orchestration for Serving LLMs Over Voice

The paper introduces llmovoice, a middleware that explicitly models voice context for large language model (LLM) serving in voice AI applications. By incorporating speaking rate, background noise, packet loss, and other paralinguistic factors into a bounded context, llmovoice guides the LLM to generate more aligned responses. Experiments show significant reductions in speaking‑rate errors, false interruptions, and model usage costs, especially in long voice sessions.

By Linyi Jiang, Silvery D. Fu, Yifei Zhu
arXiv Computation and Language
Oct 23

Towards User Simulators That Stay On Task And Still Sound Natural

The paper introduces UserLM‑2.0, a reinforcement‑learning based user simulator that balances task intent adherence with conversational naturalness. It achieves this by jointly rewarding both objectives and training a lightweight discriminator in an adversarial loop to measure naturalness. The resulting model generates valid simulated conversations 46.2% of the time, more than triple the success rate of the best prior simulator.

By Mustafa Omer Gul, Philippe Laban, Tanya Goyal, Jennifer Neville
arXiv Computation and Language
Oct 22

From Text to Voice: A Reproducible and Verifiable Framework for Evaluating Tool Calling LLM Agents

The paper introduces a reproducible framework that converts existing text-based tool‑calling benchmarks into audio‑based evaluations using text‑to‑speech, speaker variation, and environmental noise, while preserving original annotations. Experiments on seven omni‑modal models show that performance varies strongly by model and task, with notable gaps between text and voice results. The study also includes a stress test, a reference‑free LLM‑as‑judge protocol, and demonstrates that open‑source judges can match proprietary ones, aiding privacy‑preserving evaluation.

By Md Tahmid Rahman Laskar, Xue-Yong Fu, Seyyed Saeed Sarfjoo, Quinten McNamara, Jonas Robertson, Shashi Bhushan TN
arXiv Machine Learning
5d ago

Intent-Preserving Adversarial User Simulation for Multi-Turn Agent Evaluation

The paper introduces StressSim, an intent‑preserving adversarial user simulator designed to stress‑test multi‑turn agents by generating challenging yet valid user interactions. StressSim optimises high‑level adversarial plans for each task instance using a genetic prompt‑optimisation loop that leverages rollout traces, task‑completion signals, and validity feedback to reduce task success while keeping the user’s goal unchanged. Experiments on MultiWOZ, retail, and airline domains show that StressSim reveals significant robustness gaps in leading LLM agents—reducing tau‑bench pass^4 scores by up to 69%—while maintaining realistic conversation quality and goal preservation with a modest optimisation budget.

By Atri Vivek Sharma, Brian Formento, Alessio Lomuscio
arXiv Computation and Language
Sep 10

EVA-Bench: A New End-to-end Framework for Evaluating Voice Agents

arXiv:2605.13841v3 Announce Type: replace-cross Abstract: Voice agents are increasingly deployed across enterprise applications. However, no existing benchmark jointly addresses realistic conversatio...

By Tara Bogavelli, Gabrielle Gauthier Melan\c{c}on, Katrina Stankiewicz, Oluwanifemi Bamgbose, Fanny Riols, Hoang H. Nguyen, Raghav Mehndiratta, Lindsay Devon Brin, Joseph Marinier, Hari Subramani, Anil Madamala, Sridhar Krishna Nemala, Srinivas Sunkara