Wikipedia
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.
Usage examples of "vulgar latin".
If he spoke slowly and listened carefully, he and the Mallorcan could understand each other, for the Mallorcan's peculiar dialect was no more than the Vulgar Latin of old time, spoken badly and without a schoolmaster for generation after forgotten generation.