Barge-in

Without barge-in, callers have to wait until an announcement has finished. With barge-in they can correct something (“No, Thursday”) or cut a long answer short. Technically, the system keeps listening while it speaks, detects speech on the other side and stops the output. For natural conversations this is a basic requirement, because people briefly interrupt each other all the time.

The difficult part is telling a real interruption from noise: a cough, an “mhm” of agreement or background noise should not cut off the reply. Systems can therefore be tuned in their sensitivity. What happens after the interruption matters too: the system has to know which part of its answer the caller actually heard.