where did the name of the language come from?
From the term "common speech" ("sermo vulgaris")
Vulgar Latin
The term "common speech" ("sermo vulgaris"), which later became "Vulgar Latin", was used by inhabitants of the Roman Empire. 
what is geastrum quadrifidum? An inedible species of mushroom what is the origin of the name? Latin what does this species look like? The immature, unopened fruit body is roughly spherical to somewhat flattened or irregular in shape. what are its characteristics that can be observed through a microscope? Its basidia has a basal clamp connection and the spores in mass are dark brown when mature. where is the aforementioned language spoken? In the area around Rome and Italy. what are some types of that language? Old Latin, Classical Latin, Vulgar Latin and a few other. what are the ages that the second language was spoken in? Wilhelm Sigismund Teuffel defined the philological notion of it based on the metaphoric uses of the ancient myth as Ages of Man. what is unique about the vocabulary of the third language? It made some changes in spelling and case usage only.
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Vulgar Latin [SEP] Origin of the term
The term "common speech" ("sermo vulgaris"), which later became "Vulgar Latin", was used by inhabitants of the Roman Empire. Subsequently, it became a technical term from Latin and Romance-language philology referring to the unwritten varieties of a Latinised language spoken mainly by Italo-Celtic populations governed by the Roman Republic and the Roman Empire. Traces of their language appear in some inscriptions, such as graffiti or advertisements. The educated population mainly responsible for Classical Latin may also have spoken Vulgar Latin in certain contexts depending on their socioeconomic background. The term was first used improperly in that sense by the pioneers of Romance-language philology: François Juste Marie Raynouard (1761–1836) and Friedrich Christian Diez (1794–1876).