Probabilistic-Symbolic Intent Disambiguation for Robust Embodied Control under Ambiguous Speech

Speech provides a natural and flexible interface for embodied control, yet its inherent ambiguity challenges accurate task understanding and reliable execution. Meanwhile, embodied interaction continuously provides new environmental information that can further constrain plausible interpretations of the original spoken instruction. Robust speech-conditioned embodied control therefore requires an agent to continuously refine its intent understanding during execution and actively explore discriminative environmental information when competing intents lead to action disagreement. To this end, we propose a probabilistic-symbolic intent disambiguation framework, where a probabilistic measure quantifies how speech ambiguity affects action decisions, while symbolic reasoning localizes and resolves the critical intent differences underlying action disagreement through embodied interaction. Specifically, we introduce speech-induced action uncertainty to quantify how uncertainty in speech interpretation propagates to the current action decision, providing a criterion for when disambiguation is needed. We then develop a unified symbolic intent–world modeling method that maps candidate speech intents and observations into a shared symbolic space for action reasoning and intent disambiguation. Building on this representation, we introduce world-constraint alignment for speech reinterpretation, which localizes intent differences to guide targeted exploration and induces world constraints from interaction feedback to refine speech interpretations. We further introduce SPEAR-Bench, a benchmark that systematically varies perceptual, paralinguistic, and content ambiguity to evaluate task understanding and embodied control under ambiguous speech. Experiments on SPEAR-Bench and REI-Bench show that our method consistently improves task success while reducing interaction cost compared with strong baselines for embodied control under ambiguous speech.