DuplexAct: How Interactive Are Frontier Full-Duplex Spoken Language Models?

Existing full-duplex speech benchmarks cover only subsets of real-time interaction behaviors, often under limited contextual conditions. We introduce DuplexAct-Bench, a bilingual benchmark that systematically covers six complementary behaviors, from interruption and yielding to proactive initiation, active silence, and backchanneling, across Pre-session, In-session, and No-explicit conditions. Across 1,290 English and Chinese streaming trials, we evaluate 12 full-duplex speech systems on both Timing and Content. Results reveal substantial variation across behaviors, conditions, and systems, as well as frequent mismatches between semantic quality and behavioral timing. These findings show that current systems remain far from robustly managing when, whether, and how to participate as real-time interaction unfolds. Project page: https://alitaxky.icu/DuplexAct-Bench/

Real-time full-duplex speech models can listen while speaking, enabling natural interaction without rigid turn boundaries. Existing benchmarks evaluate turn-taking, interruption handling and multi-round dialogue, but largely centre on a designated user rather than an assistant participating in a shared conversation among several people. We introduce Duplex-MPE to evaluate when such an assistant should answer, remain silent or stop speaking. The benchmark contains 2,000 scenarios with three or four human speakers and one assistant, each paired across explicit and implicit addressing of the same request. Models receive continuous conversation audio without transcripts or supplied turn boundaries. Four scores measure fresh response initiation, answer accuracy, silence preservation and stopping when a human resolves a request. We evaluate five open-weight speech systems: MiniCPM-o 4.5, Moshi, FLM-Audio, Voila and Freeze-Omni. MiniCPM-o 4.5 leads on three scored capabilities, while frequent speech from other systems can coexist with inaccurate answers or failures to remain silent. A transcript-based Gemini 3.1 Pro reference responds 64.3 percentage points more often to explicit than implicit requests; paired tests detect no significant response-rate difference for the speech systems.

Full-duplex spoken dialogue systems (FDSDSs) can listen while speaking, enabling natural conversational behaviors such as smooth turn-taking, backchannel handling, and user barge-in handling. However, controlled comparisons of FDSDSs in multi-turn interaction remain challenging, and existing benchmarks offer limited joint coverage of multiple languages, dialogue settings, interaction timing, and response content. We propose M3-DuplexBench, a multi-turn, multilingual, multidomain benchmark for controlled evaluation of FDSDSs. The benchmark jointly evaluates interaction timing and response content in English and Japanese across casual conversation and multi-turn question answering. The English and Japanese question-answering data are derived from a common source corpus, enabling cross-lingual comparisons of timing and content performance. We also provide a reference-conditioned multi-turn setting as an optional diagnostic for examining sensitivity to dialogue history and trajectory mismatch. Experiments with diverse FDSDSs reveal model-specific interaction patterns, differences across languages and domains, and model-dependent effects of dialogue context on both timing and content. The benchmark is available at https://github.com/nttcslab-sp/m3-duplexbench.