How is Vulgar Latin different from Classical Latin?

Vulgar Latin, the spoken form of non-Classical Latin that served as the ancestor to the Romance languages, differed from Classical Latin in several key areas of grammar, vocabulary, and phonology.12

Linguistic Differences

• Vocabulary: Vulgar Latin favored more expressive, popular terms over the sober, formal vocabulary of Classical Latin. For example, portare ("to carry") was preferred over ferre, and cantare ("to sing") replaced canere.1
• Grammar: Synthetic constructions, which relied on complex case endings, were increasingly replaced by analytic structures using prepositions. This simplification made case endings largely superfluous, and word order became less flexible than in the Classical period.1
• Phonology: The most significant change was the loss of the system of long and short vowels, which fundamentally altered the language's rhythm. Additionally, a strengthening of stress accents led to the shortening or loss of unaccented syllables (e.g., viridem becoming virdem). Other features included the loss of word-final -m and the reduction of certain diphthongs.1

While Classical Latin was codified for literary and oratorical use, Vulgar Latin represented the evolving, colloquial speech of the Roman Empire's diverse populations.12