Put yourself in a scene with four other people. Place yourself off to one side, able to observe the others unobtrusively. Now remove all of the audio. Cheryl is looking at her mother, mouthing the occational phrase. When she’s not using it for speech she’s using it to cannibalize her fingers. Cheryl’s mother is driving. Her eyes are obscured by dark sunglasses, but you can sense her attention scanning the setting by the subtle movements of her head presumably following the tracking of her eyes. Joe has taken up his trademark “being a good sport” pose: one hand resting on his stomach supporting the other, which in turn is cradling his chin in it’s palm. Do you ever get the feeling that someone is talking to you?