Most voice agents decide you are done talking by measuring silence. Voice activity detection flags the audio as speech or not speech, a timer runs during the not-speech, and when the timer crosses a threshold the turn ends and generation begins.
It is a reasonable first architecture. It is also wrong in a way that gets worse the more natural the conversation gets.
The failure looks like this. Someone is thinking while they speak. They pause mid-sentence, because that is what people do when they are constructing a thought rather than reading one out. The pause crosses the threshold. The system ends the turn and starts responding, and the user gets cut off by a machine, mid-thought.
The fix that presents itself immediately is to raise the threshold. Wait longer before deciding the turn is over.
This is the part worth writing down: raising the threshold trades one failure for a worse one. Latency in conversation is not a smooth cost curve. Below a certain point people do not perceive a delay at all. Above it, they perceive a system that is slow, and slowness in a voice interface reads as broken in a way that visual latency does not, because there is no spinner, no loading state, nothing to indicate the machine is alive. Silence from a voice agent is indistinguishable from failure. So you push the threshold up to stop the interruptions, and you lose the thing that made the product feel real.
