Vulgar Latin

Vulgar Latin or Sermo Vulgaris ("common speech") is a generic term for the nonstandard (as opposed to classical) sociolects of Latin from which the Romance languages developed. Works written in Latin during classical times used Classical Latin rather than Vulgar Latin, with very few exceptions (most notably sections of Gaius Petronius' Satyricon). Because of its nonstandard nature, Vulgar Latin had no official orthography. Vulgar Latin is sometimes also called colloquial Latin, or Common Romance (particularly in the late stage). In Renaissance Latin, Vulgar Latin was called vulgare Latinum or Latinum vulgare.

Proto-Romance

Vulgar Latin is often confused with Proto-Romance. Proto-Romance is a proto-language, i.e., the latest stage common to all of the Romance languages. Because some of the less familiar Romance languages branched off earlier than others (Sardinian in particular), followed by Romanian and related Eastern Romance languages, it is also common to reconstruct later stages: e.g., Proto–Continental Romance (after Sardinian branched off); Proto–Italo-Western Romance (after Sardinian and Romanian branched off); and Proto–Western Romance (after the branching-off of Sardinian, Romanian, and the central and southern Italian languages, including standard Italian).