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Main Authors: Qian, Livia, Skantze, Gabriel
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2604.16622
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author Qian, Livia
Skantze, Gabriel
author_facet Qian, Livia
Skantze, Gabriel
contents Backchannels (e.g., `yeah', `mhm', and `right') are short, non-interruptive feedback signals whose lexical form and prosody jointly convey pragmatic meaning. While prior computational research has largely focused on predicting backchannel timing, the relationship between lexico-prosodic form and meaning remains underexplored. We propose a two-stage framework: first, fine-tuning large language models on dialogue transcripts to derive rich contextual representations; and second, learning a joint embedding space for dialogue contexts and backchannel realizations. We evaluate alignment with human perception via triadic similarity judgments (prosodic and cross-lexical) and a context-backchannel suitability task. Our results demonstrate that the learned projections substantially improve context-backchannel retrieval compared to previous methods. In addition, they reveal that backchannel form is highly sensitive to extended conversational context and that the learned embeddings align more closely with human judgments than raw WavLM features.
format Preprint
id arxiv_https___arxiv_org_abs_2604_16622
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Aligning Backchannel and Dialogue Context Representations via Contrastive LLM Fine-Tuning
Qian, Livia
Skantze, Gabriel
Computation and Language
Artificial Intelligence
Machine Learning
Backchannels (e.g., `yeah', `mhm', and `right') are short, non-interruptive feedback signals whose lexical form and prosody jointly convey pragmatic meaning. While prior computational research has largely focused on predicting backchannel timing, the relationship between lexico-prosodic form and meaning remains underexplored. We propose a two-stage framework: first, fine-tuning large language models on dialogue transcripts to derive rich contextual representations; and second, learning a joint embedding space for dialogue contexts and backchannel realizations. We evaluate alignment with human perception via triadic similarity judgments (prosodic and cross-lexical) and a context-backchannel suitability task. Our results demonstrate that the learned projections substantially improve context-backchannel retrieval compared to previous methods. In addition, they reveal that backchannel form is highly sensitive to extended conversational context and that the learned embeddings align more closely with human judgments than raw WavLM features.
title Aligning Backchannel and Dialogue Context Representations via Contrastive LLM Fine-Tuning
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2604.16622