@inproceedings{liu-etal-2026-ped,
    title = "{PED}: Route-Decoupled Diagnostics for Persona Consistency in Spoken Agents",
    author = "Liu, Weihao  and
      Wei, Junrui  and
      Zhang, Zhao  and
      Zhang, Ju",
    editor = "Liakata, Maria  and
      Moreira, Viviane P.  and
      Zhang, Jiajun  and
      Jurgens, David",
    booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {ACL} 2026",
    month = jul,
    year = "2026",
    address = "San Diego, California, United States",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/ingest-acl/2026.findings-acl.445/",
    pages = "9155--9168",
    ISBN = "979-8-89176-395-1",
    abstract = "Maintaining a stable persona is central to sustained spoken role-playing, yet when an agent breaks character, current evaluations often do not isolate which component caused the failure, making fixes slow and ad hoc.We propose PED (Persona-Emotion Decoupling), a diagnostic evaluation framework that decomposes persona expression into two observable routes: what the agent says (text) and how it sounds (speech).PED operationalizes the affective slice of persona expression by projecting transcripts and audio into a shared affective measurement space for route-comparable, reference-based analyses of separability, drift, failures, and coupling.We demonstrate PED via two worked instantiations spanning an end-to-end Speech LLM and a cascaded LLM+TTS pipeline under a fixed dialogue protocol.Within this setting, PED surfaces four recurring diagnostic signatures:(i) route-level separability is bounded by reference overlap and can differ sharply across architectures,(ii) text-route drift is stress-linked and tends toward a neutral-heavy region,(iii) text-audio consistency is weakly coupled, yielding route-asymmetric failures,and (iv) audio-route structure can be materially shaped by an explicit intermediate style cue in cascaded pipelines.Overall, PED reframes holistic ``voice+character'' grading as turn-level, fault-localizing signals for faster debugging and iteration."
}