Commentary Inf II 56-57

Virgil describes Beatrice's speech as being soave e piana (gentle and clear). She will, in turn, describe his speech as parola ornata (polished words -- [Inf II 67]). The two adjectives, piana and ornata, may remind us of a major distinction, found in medieval categorizations of rhetorical styles, between the plain, or low, style, and the ornate, or high. Benvenuto (DDP Benvenuto.Inf.II.56) was the first to point this out, glossing 'soave e piana' as follows: 'divine speech is sweet and humble, not elevated and proud, as is that of Virgil and the poets.' Thus Virgil's description of Beatrice's words corresponds antithetically to hers of his; her speech represents the sublimely humble style valorized by the Comedy, while his recalls the high style that marked pagan eloquence (the observation is drawn from Holl.1990.2, p. 107, where there are references to previous discussions in Auer.1958.1, pp. 65-66; Mazz.1979.1, pp. 157-158).

For Boccaccio's notion that Beatrice's favella (speech) was in fact the Florentine vernacular see DDP Padoan.Inf.II.57.