Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
I have already spoken of the interchange of letters [*](I. iv. 12–17.) and need not repeat my remarks here: perhaps their pronunciation corresponded with their spelling.