Question: What is one of Boccaccio's works that helped promote the Italian language?
Answer: The application of the vernacular did not entail a rejection of Latin, and both Dante and Boccaccio wrote prolifically in Latin as well as Italian, as would Petrarch later (whose Canzoniere also promoted the vernacular and whose contents are considered the first modern lyric poems).
A single-select problem: Is the question answered in a satisfactory fashion?

Choose your answer from: (i) yes; (ii) no;
(ii)