A、Sound change can be a signal for social and cultural identity. B、A group of people will pronounce some certain words that have

M: The last theory advanced during the last century is a social one, advocated by the American linguist William Labov. What he found was that at the beginning a small part of a population pronounces certain words that have, for example, the same vowel, differently man the rest of the population. This occurs naturally since humans don’t all reproduce exactly the same sounds. However, at some later point in time, for some reason this difference in pronunciation starts to become a signal for social and cultural identity. Others of the population who wish to be identified with the group either consciously or unconsciously adopt this difference, exaggerate it, and apply it to change the pronunciation of other words. If given enough time, the change ends up affecting all words that possess the same vowel so that this becomes a regular linguistic sound change.
I: This is a lot more reasonable.
M: Right. And similar phenomena apply to the grammar and to the lexicon of languages. An interesting example is that of computer-related words creeping into standard American language, like "bug", "crash", "net", "email", etc. These words were originally used by computer scientists, but with the boom in the Internet everybody wants to become technology-sawy. So these computer science words start to filter into the mainstream language.
I: Among all the above mentioned theories, which one do you advocate?
M: The social theory, of course. Humans are, after all, social animals, and rarely do things without a social factor.
I: Well, Michael, thank you very much for telling us so much valuable information about language change.
M: You’re welcome.
6. Which one is TRUE about social theory of language change?
7. According to William Labov, which statement is WRONG?
8. Why does computer language start to filter into the standard language?
9. What is Michael’s attitude towards the social theory of language change?
10. How many scientific explanations of language change are introduced by Michael?