I swear I sometimes hear one talking over a preset synchronized reaction sound. It's not only the perfect timing, it's the perfect phrasing, intonation and choice of reaction. Sounds like a bunch of audio files being randomly triggered at times. I'm not going schizo. Just listen to the next minute of this and tell me it sounds natural:
https://www.youtube.com/live/rVNL6MJBQvk?feature=share&t=4241