BiCon-Gate: Consistency-Gated De-colloquialisation for Dialogue Fact-Checking

arXiv cs.CL / 4/17/2026

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Key Points

The paper targets automated multi-turn dialogue fact-checking where colloquial language is common but insufficiently studied, proposing a staged “de-colloquialisation” step to generate rewrite candidates for each claim.
It introduces BiCon-Gate, a semantics-aware consistency gate that only adopts a rewritten claim when it is semantically supported by the dialogue context, otherwise using the original claim to stay conservative.
The method combines lightweight surface normalization with scoped in-claim coreference resolution to improve the quality and reliability of rewrite candidates.
Experiments on the DialFact benchmark show improvements in both evidence retrieval and fact verification, with especially strong gains on SUPPORTS, outperforming several baselines including a decoder-based one-shot LLM rewriting approach.
The gated rewriting strategy is designed to stabilize downstream fact-checking, reducing semantic drift that could otherwise hurt retrieval and verification.

Abstract

Automated fact-checking in dialogue involves multi-turn conversations where colloquial language is frequent yet understudied. To address this gap, we propose a conservative rewrite candidate for each response claim via staged de-colloquialisation, combining lightweight surface normalisation with scoped in-claim coreference resolution. We then introduce BiCon-Gate, a semantics-aware consistency gate that selects the rewrite candidate only when it is semantically supported by the dialogue context, otherwise falling back to the original claim. This gated selection stabilises downstream fact-checking and yields gains in both evidence retrieval and fact verification. On the DialFact benchmark, our approach improves retrieval and verification, with particularly strong gains on SUPPORTS, and outperforms competitive baselines, including a decoder-based one-shot LLM rewrite that attempts to perform all de-colloquialisation steps in a single pass.