Castiglione was convinced that the moral qualities of the courtier could and should be immediately reflected in his communication: in the name of integrity and personal rectitude, he reputed that it was opportune that every individual should shape his communication skills until they became the natural transposition of his interiority. This is ratified in the second book of The Cortegiano by what he says about clothes. And it is even more pertinent, according to what he writes in the first book of the work, for the question of language. How should the perfect courtier speak and write? The duty of replying is given by Castiglione to the character of Ludovico di Canossa, who, in antithesis to the archaic thesis of Federico Fregoso (spokesperson for Bembo), exposes the ideas of he author.
In his linguistic choices, first of all, the courtier must avoid affectations: this means that he must avoid the obvious imitation of models, even if excellent, from the past. What counts in the process of communication, on the contrary, is the rule that bans the use of expressions that have by now fallen into disuse, as they procure irritation and unease. There follows a eulogy of the evolution and variability of language: perfection cannot be achieved completely following a model, thus each person, understanding the prohibition of using forms that are extraneous to common usage, is allowed to forge his own way of speaking and writing. What had been verified reflecting on contemporary painting was valid also for language: there is no immutable prototype, which, by virtue of a presumed superiority, must be indiscriminately copied.
Language is in perpetual change, and what was perfect for ancient writers in no longer so today: a gentleman must therefore not seek to make his choices based on the pages of the great authors of the past, as on the basis of the ideas of Bembo is maintained by Federico Fregoso, but on the entire material of living language, used in common speech. Furthermore, language is permeable and flexible, and Castiglione, from this point of view, considered any rigidity absurd: if it is to be congruent with the interior world of the person using it, we must promote the respect of individual stylistic dispositions.