Why did Latin literary language become increasingly different from everyday speech?

In the context of Western literature, the divergence between Latin literary language and everyday speech occurred because the former was a highly codified, standardized idiom, while the latter—often referred to as Vulgar Latin—continued to evolve naturally through regional and social variation.123

During the Classical period, Latin literature became increasingly refined, with grammarians codifying rules, pruning vocabulary, and emphasizing an elegant, balanced prose style. This literary standard was deliberately maintained as a uniform, prestigious medium for scholarship and administration.123

Conversely, spoken Latin was subject to constant change in phonology, grammar, and vocabulary. Over time, these shifts—such as the loss of vowel-length distinctions, the simplification of synthetic case endings into analytic constructions, and the adoption of more colloquial, expressive terms—created a widening gap between the written "Classical" norm and the living, spoken language. By the 8th or 9th century, this evolution reached a point where speakers finally recognized that the standardized literary language was a distinct entity from their own vernacular, eventually leading to the emergence of the Romance languages.42153