Miguel de Cervantes (1547-1616), "Dialogue between Scipio and Berganza, Dogs of the Hospital of the Resurrection in the City of Valladolid, Commonly Called the Dogs of Mahudes," Exemplary Novels
(tr. Walter K. Kelly):
Berg. What I have to remark is, that as I was the whole day at leisure—and leisure is the mother of reflection—I conned over several of those Latin phrases I had heard when I was with my masters at college, and wherewith it seemed to me that I had somewhat improved my mind; and I determined to make use of them as occasion should arise, as if I knew how to talk, but in a different manner from that practised by some ignorant persons, who interlard their conversation with Latin apophthegms, giving those who do not understand them to believe that they are great Latinists, whereas they can hardly decline a noun or conjugate a verb.
Scip. That is not so bad as what is done by some who really understand Latin; some of whom are so absurd, that in talking with a shoemaker or a tailor, they pour out Latin like water.
Berg. On the whole we may conclude, that he who talks Latin before persons who do not understand it, and he who talks it, being himself ignorant of it, are both equally to blame.
Scip. Another thing you may remark, which is that some persons who know Latin are not the less asses for all that.
Berg. No doubt of it; and the reason is clear; for when in the time of the Romans everybody spoke Latin as his mother tongue, that did not hinder some among them from being boobies.
Scip. But to know when to keep silence in the mother tongue, and speak in Latin, is a thing that needs discretion, brother Berganza.
Berg. True; for a foolish word may be spoken in Latin as well as in the vulgar tongue; and I have seen silly literati, tedious pedants, and babblers in the vernacular, who were enough to plague one to death with their scraps of Latin.