Enhancing Speech-to-Speech Dialogue Modeling with End-to-End Retrieval-Augmented Generation
Pengchao Feng, Ziyang Ma, Wenxi Chen, Yao Li, Sheng Wang, Kai Yu, Xie Chen
TL;DR
This work tackles end-to-end speech-to-speech dialogue by introducing a retrieval-augmented generation framework that directly retrieves textual knowledge from speech through a shared embedding space. Leveraging a multimodal encoder (SONAR), the approach eliminates ASR bottlenecks to achieve significant retrieval speedups while preserving substantial knowledge grounding. Empirical results on multilingual QA benchmarks show meaningful improvements over non-RAG baselines, though the end-to-end method still trails ASR-based cascades in some metrics. Ablation studies emphasize the importance of semantic alignment in the shared space, and the authors release code and data to encourage further research in this direction.
Abstract
End-to-end speech-to-speech (S2S) dialogue systems have recently garnered increasing research attention for their lower latency and more natural integration of nonverbal cues such as emotion and speaker identity. However, these systems face key challenges, particularly in incorporating external knowledge, a capability commonly addressed by Retrieval-Augmented Generation (RAG) in text-based large language models (LLMs). The core difficulty lies in the modality gap between input speech and retrieved textual knowledge, which hinders effective integration of information. To address this issue, we propose a novel end-to-end RAG framework that directly retrieves relevant textual knowledge from speech queries. Experimental results demonstrate that our method significantly improves the performance of end-to-end S2S dialogue systems while achieving higher retrieval efficiency. Although the overall performance still lags behind the SOTA cascaded models, our framework offers a promising direction for enhancing knowledge integration in end-to-end S2S systems. Our code and dataset are released.
