I'm starting to understand this "text level grammar" of Johanna's, as
described below.

Sometimes a writer might follow three or four long sentences with a
really short one that ties in all of the points.  Or, a writer might use
similar grammatical structures over a span of text in order to format
the ideas in a certain way for the reader, or else to build ideas
within a controlled structure.

If we do a grammatical analysis of all of the sentences within a
whole paragraph, we will discover all sorts of things about the
handling of information and communication.  The style of an author
is seen not only in individual sentences, but in the combination of
sentence patterns.  I think I've got it!

Sorry it took me 5 years to clue in.

>the relation between text
> structure (paragraphs and larger) and sentence-level choices. There are
> two good questions to start with: a) How does (or just 'does') the choice
> of subject in each sentence help maintain topic and subtopic thread by
> naming a topic/subtopic? b) Are there consistent grammatical roles used to
> maintain mention of already-introduced ideas/entities vs. to introduce new
> information about them (the 'news' or ideas about the topic(s) that the
> writer wishes to convey)? And to connect the new ideas to the correct
> topics/subtopics?