Surely there are many interpretations of these sorts of phenomena, however semiotics seems apt based on your explanation/how you seem to be thinking about this. From the paradigm of topological semiotics, communicating to convey information is much like plotting points (albeit more like diffuse regions) on a high-dimensional map, in which the intersection along the axes of these points at any particular moment is the approximate position of the intended information. This relies on the similarity of comprehensible space between communicators, the variance of which, although it may seem vast in experience, is contrariwise much more akin to genetic variance among a particular species. Nevertheless, general relativity precludes any two identical comprehensible spaces (one might simply say 'human minds' or 'experiences of existence'), which Descartes loosely identified as the origin of the differences of opinions. Since our 'maps' are not the same, one can speak words that point to a concept either within or without a listener's comprehensibility. In the latter case, other points must first be located (e.g. other words must first be spoken) such that the intersection along their axes can point to this new territory. Both are guiding the listener's mind toward the intended point; the difference is that a point already existing within comprehensible space can be recollected, and may be based on experiential observation, while attempting to reach a point outside of comprehensible space requires building a support structure, which is the understandings of regions necessary for incorporating the new terrain into one's map. As you can see, one requires guiding the listener, while the other can be almost directly accessed (walked right up to, so to speak).
Looking at the first bit of dialogue, semiotics would say that the physical motions of the listener are communication, merely non-verbal. The speaker might consider these unspoken coordinates (communications) from the listener as an affirmation that the listener is able to locate the intersection of meaning of the current target interpretant (e.g. concept in the mind), and that the process of moving along these thoughts to the target has raised in their sensibilities no errors, which is to say that the speaker believes that the listener believes that they understand what the speaker means. This action can be seen as a shared navigation, which attempts to rectify topological variance in comprehensible space; since speech is more salient to our attention than most non-verbal communications, it's easy to think that the speaker is the sole navigator for the exchange, but of course they seldom are. Anyway, this is real-time conversation modulation, although a specific term doesn't readily come to mind.
In your example, whether the listener intends to produce feedback is irrelevant, because the action of inferring feedback takes place within the speaker's mind; the listener may stay as still as a statue, which may seem like no signal, but spacetime keeps expanding; there is a signal nevertheless, and one that will be interpreted as having meaning on account of the learned expectation of exchange in conversation. In other words, the speaker cannot cease receiving signals, and, in receiving signals, will necessarily have expectations on account of having had conversations previously. Whether these signals converge toward or diverge from expectations, they will invariably modulate the speaker's thoughts, and thereby words. After all, reality is continuous.
Of course, this is just one school of thought. I hope that I've understand your meanings well enough for that all to make sense and some amount of contribution!
