Since most of you don’t understand my distinctions between the proto-Cantonese and the VietNamese, and what I mean by “VietNamese being a nomenclature”, and insist upon being spoon-fed, very well...
First, if you look at Keith Weller Taylor’s theories on how the “Yue” of the south got their names: He claims that the tribes known as the “Yue” (right under the central plains, but not as far south as what would become “LingNam”), pushed their way southwards, when the Chinese took their land. In turn, they conquered these people, set up their forms of government, and these people also became known as the “Yue”. (He also provides footnotes to Western examples of such incidences happening, where a small minority of people, attack a majority, winning, and then setting themselves up as the elites of the society…) Hence, his view follows tightly with the view held by Chinese historians, only with a minor twist. Then if you read on, he basically says the “Lac” of “Lac Viet” took on the term “Viet” for themselves, because Lac was something only used by their own people, and wasn’t at all familiar to the Chinese. So, to be recognized in Chinese politics, they took on the nomenclature “Viet”.
Although this isn’t a bad idea, this is my theory on how the nomenclature of "Yue" came about for the proto-Cantonese and the "Yue" north of them...
First of all, if you look at the definition of 越...
Obviously, the Chinese were very clear on something that was "outside" their boundaries. Now remember, Chinese interaction with these cultures were quite limited (aside from a few trades of goods and whatnots). So what they understood was quite vague, except for the fact that these people had tattoos, and different hairstyles. When the Chinese conquest of the south began, they began to notice more differences between these people, however there were still those "underlying similarities" between these people, that they perceived all to have originated from the same 越 (Yue) culture. Here's the tricky part:
A (what the Chinese believe): The Yue were either sinicized completely, or displaced by the Chinese away from their homeland. Seeing this, the "Yue" began to bundle further south (Hence, that whole "Hundred Yue"["Bach Viet"] idea pops up).
B (What most likely happened)- As the Chinese successfully sinicised the people who were in these regions, they slowly became assimilated, and you begin to see the assimilation in a "trickle down" affect. Granted, there may have been some people who escaped this fate and did as the Chinese claimed, most likely, they weren't displaced, allowing huge waves of "Yue" crowding up space. (Most likely, this "fleeing model", must have been thought to be something universal by the Chinese, since they always seem to do it often, to avoid conflict).
So in other words, without knowing who these people were, they just called them something, and the name stuck.·*
This "fleeing model" is constantly used throughout China's conquest in the south, in belief that these people all shared the same culture, and fled to each other in face of Chinese expansion. If this fleeing model were true, "Where exactly did the 'Yue' in VietNam flee to when the Chinese took their land?" Obviously, these people must have stayed behind, or else they wouldn't have been able to put up vigorous fights against the Chinese government.
"Well then, how did the VietNamese come about with taking the term 'Viet' (Yue) to identify themselves?"
Now, going back to Keith Weller Taylor, remember that the VietNamese called themselves the "Lac". To which, when heard by the Chinese people, must have remarked "What's a 'Lac'?" So, we can either follow Keith Weller Taylor's model of taking up the nomenclature for political reasons, to be recognized, or we could go back to my "Indian nomenclature model"·*, where the Chinese were dead-sent upon naming these people such, that the name actually grew upon them.
·* Similar to Christopher Colombus landing in America (thinking he'd arrived at India) and calling the Natives, "Indians" --to which this nomenclature still sticks with these people, even among themselves. This term has stuck so strongly with them, that sometimes, they make it "half politically correct", calling themselves, "American Indians", instead of "Native Americans". <--"Indian-nomenclature model"