From Fluency to Communicative Competence: Designing Conversational Agents for High-Stakes Dialogue

PhD Thesis Proposal Defence


Title: "From Fluency to Communicative Competence: Designing Conversational
Agents for High-Stakes Dialogue"

by

Mr. Dingdong LIU


Abstract:

Recent large language models have given conversational agents (CAs)
open-domain fluency, expanding the range of dialogue tasks they can take on.
Yet fluency in producing language does not by itself amount to communicative
competence: the ability to coordinate turns, sustain mutual engagement, and
elicit what users do not explicitly say. This thesis takes up the challenge
of moving CAs from fluency to communicative competence.

We focus on a class of interactions in which the agent is taking on, or
working alongside, portions of work normally performed by trained
practitioners. Taking healthcare dialogue as the empirical setting and
drawing on theories of dialogue grounding, we argue that communicative
competence operates at two coupled levels: a coordination level
(turn-taking, engagement) and a content level (eliciting and aligning latent
intent). These form a cascade in which progress at one level introduces new
demands at the other.

The thesis develops this argument through five studies. Papers 1 and 2
address coordination-level competence: Paper 1 presents an inter-pausal-unit
and behavioral-cue architecture for floor coordination in humanoid-robot
patient interviews, with interaction rules derived from clinician co-design;
Paper 2 generalizes it with multimodal LLM-driven dynamic prompting for
stance estimation. Papers 3 and 4 advance content-level competence: Paper 3
designs scaffolding for self-report in hospital admission interviews,
grounded in expert input; Paper 4 derives comparable scaffolding from
large-scale telehealth data via a heterogeneous-graph approach. Paper 5
contributes a diagnostic taxonomy of communication breakdowns from a
deployment study of automated neurocognitive disorder screening. Throughout,
we combine clinician co-design, system building, and mixed-methods user
studies.

The thesis offers a view of human-CA communication in which coordination and
content competence are coupled and in which much of what matters is not
explicitly stated. It contributes systems for participating in such dialogue
and a framework for understanding where competence can and cannot yet be
expected.


Date:                   Wednesday, 10 June 2026

Time:                   4:00pm - 6:00pm

Venue:                  Room 5501
                        Lift 25/26

Committee Members:      Dr. Xiaojuan Ma (Supervisor)
                        Prof. Fugee Tsung (Co-supervisor, IDEA)
                        Dr. Xiaomin Ouyang (Chairperson)
                        Dr. Chaojian Li