As to linearity of language. Harvey Sachs was a colleague and friend
who wrote a lot about conversation. Ever hear him give a talk? He
couldn't do it very well. The non-linearity of the phonemena were
so prominent in his thinking that he had a hard time getting a sentence
out.
So, sure, you are right. But still, there are constraints on production
and reception that make it a little difficult to say or hear everything
at once.
mike