Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
What, then, will be the difference between what is written and what is spoken? If I were given a jury of wise men, I should cut down a large number of passages from the speeches not only of Cicero, but even of Demosthenes, who is much more concise.
Since, however, our judges are the people, or drawn from the people, and since those who are appointed to give sentence are frequently ill-educated and sometimes mere rustics, it becomes necessary to employ every method that we think likely to assist our case, and these artifices must not merely be produced in speech, but exhibited in the written version as well, at least if in writing it our design is to show how it should be spoken.
If Demosthenes or Cicero had spoken the words as they wrote them, would either have spoken ill And is our acquaintance with either of those two great orators based on anything save their writings? Did they speak better, then, or worse than they wrote? If they spoke worse, all that can be said is that they should have spoken as they wrote, while, if they spoke better, they should have written as they spoke.