structural:scholar_edition, quality:correction
Use of language

The novel's farcical elements make use of punning and similar verbal playfulness. Character-naming in Don Quixote makes ample figural use of contradiction, inversion, and irony, such as the names Rocinante (a reversal) and Dulcinea (an allusion to illusion), and the word quixote itself, possibly a pun on quijada (jaw) but certainly cuixot (Catalan: thighs), a reference to a horse's rump.

As a military term, the word quijote refers to cuisses, part of a full suit of plate armour protecting the thighs. The Spanish suffix -ote denotes the augmentative—for example, grande means large, but grandote means extra large, with grotesque connotations. Following this example, Quixote would suggest 'The Great Quijano', an oxymoronic play on words that makes much sense in light of the character's delusions of grandeur.

Cervantes wrote his work in Early Modern Spanish, heavily borrowing from Old Spanish, the medieval form of the language. The language of Don Quixote, although still containing archaisms, is far more understandable to modern Spanish readers than is, for instance, the completely medieval Spanish of the Poema de mio Cid, a kind of Spanish that is as different from Cervantes' language as Middle English is from Modern English. The Old Castilian language was also used to show the higher class that came with being a knight errant.

In Don Quixote, there are basically two different types of Castilian: Old Castilian is spoken only by Don Quixote, while the rest of the roles speak a contemporary (late 16th century) version of Spanish. The Old Castilian of Don Quixote is a humoristic resource—he copies the language spoken in the chivalric books that made him mad; and many times, when he talks nobody is able to understand him because his language is too old. This humorous effect is more difficult to see nowadays because the reader must be able to distinguish the two old versions of the language, but when the book was published it was much celebrated. (English translations can get some sense of the effect by having Don Quixote use King James Bible or Shakespearean English, or even Middle English.)

In Old Castilian, the letter x represented the sound written sh in modern English, so the name was originally pronounced. However, as Old Castilian evolved towards modern Spanish, a sound change caused it to be pronounced with a voiceless velar fricative sound (like the Scots or German ch), and today the Spanish pronunciation of "Quixote" is. The original pronunciation is reflected in languages such as Asturian, Leonese, Galician, Catalan, Italian, Portuguese, Turkish and French, where it is pronounced with a "sh" or "ch" sound; the French opera Don Quichotte is one of the best-known modern examples of this pronunciation.

Today, English speakers generally attempt something close to the modern Spanish pronunciation of Quixote (Quijote), as / k iː ˈ h oʊ t i /, although the traditional English spelling-based pronunciation with the value of the letter x in modern English is still sometimes used, resulting in / ˈ k w ɪ k s ə t / or / ˈ k w ɪ k s oʊ t /. In Australian English, the preferred pronunciation amongst members of the educated classes was / ˈ k w ɪ k s ə t / until well into the 1970s, as part of a tendency for the upper class to "anglicise its borrowing ruthlessly". The traditional English rendering is preserved in the pronunciation of the adjectival form quixotic, i.e., / k w ɪ k ˈ s ɒ t ɪ k /, defined by Merriam-Webster as the foolishly impractical pursuit of ideals, typically marked by rash and lofty romanticism.