Why ChatGPT Keeps Interrupting You — Dr. Tom Shapland, LiveKit
Jul 31, 2025 · 27:03
Dr. Tom Shapland of LiveKit explains why voice AI agents like ChatGPT's Advanced Voice Mode keep interrupting users: they rely on a simple VAD that triggers after a silence threshold, unlike humans who predict turn endings using semantics, syntax, and prosody. To solve this, LiveKit developed a semantic end-of-utterance model that considers the last four conversation turns, extending the VAD's silence window when the user is not done. A side-by-side demo shows dramatic reduction in interruptions. Shapland contrasts this with full-duplex models like Moshi and Meta's SyncLLM, which process input and generate speech simultaneously but lack instruction-following. He predicts commercial systems will improve via smarter VAD augmentations and faster cascade pipelines, not full-duplex. The talk also covers handling backchannels (e.g., 'mm-hmm'), the challenge of benchmarking turn-taking, and why OpenAI doesn't yet use LiveKit's model.
