To revise a sentence a writer must have a way, a place, a strategy for breaking into it, but beginning writers tend to experience their sentences as unmanageable streams of words which, once set in motion, cannot be turned back. Thus injunctions to revise or reword or even proofread passages often produce merely neater copies of the same sentences, not because the student is recalcitrant but because he does not "see" the parts within his sentences that need re-working. He sees no seams nor joints nor points of intersection--only irrevocable wholes.

[. . . ]

As an extension of speech, writing does, of course, draw heavily upon a writer's competencies as a speaker--his grammatical intuitions, his vocabulary, his strategies for making and ordering statements, etc., but it also demands new competencies, namely the skills of the encoding process (handwriting, spelling, punctuation) and the skill of objectifying a statement, of looking at it, changing it by additions, subtractions, substitutions, or inversions, taking the time to get as close a fit as possible between what he means and what he says on paper.

Errors and Expectations, 1977, p. 78-79