Consciousness Levels

Speaking of levels of consciousness (as the previous post did) one of the common examples used by cognitive psychologists to illustrate different levels runs as follows:

Suppose you are driving around town with your spouse in the front seat. You (as the driver) can carry on a perfectly reasonable, fluent, intelligent conversation with your spouse even while navigating traffic, correctly obeying signs and lights, making turns as needed, operating brakes, turn signals, clutch if necessary, etc. You successfully carry out all these perceptual and mechanical or physical operations virtually at a subconscious level even while focusing on the conversation with your spouse. We've all done it, or something like it.
But now suppose you are asked to very consciously focus visually on the traffic signs, street scenes, vehicles around you, and general traffic environment (as if there was going to be a pop quiz later). You would now find it VERRRY difficult to simultaneously carry on such a fluid, intelligent conversation with your spouse; a choppy, halting conversation maybe, but not the smooth, continuous, proficient communication as before. In short, an experienced driver can attend to the perceptual requirements of a traffic environment around him/her successfully in a fairly automatic, ingrained manner, but language, on the other hand, is a learned cerebral activity that requires more direct conscious attention and control --- and this is so even though language is itself very automatic (one does not consciously think about grammatical and semantic rules when conversing), just not as automatic in the same way or degree as various visual and physical activity. Different levels of consciousness, and different parts/structures of the brain are involved.