Background
Nowadays, I see "them" used to mean "those" a lot. I don't know if it was as common in the past.
For example, take "one of them people".
On researching about it, I found some people say it comes from a dialect of British English. Some others say it is a "non-standard" usage.
I see this usage in Canadian English also, and it seems some people use it in a sarcastic way.
Moreover, I have seen a song titled "one of them days". I also read, in the book called "A Broken Promise", "Now my mother had become one of them people."
Finally, Wikipedia says that it is a usage in Appalachian English (a common name for the Southern Midland dialect of American English):
Pronouns and demonstratives
"Them" is sometimes used in place of "those" as a demonstrative in both nominative and oblique constructions. Examples are "Them are the pants I want" and "Give me some of them crackers."
Question(s):
What would you say about the usage of this word? Is it correct? Could we use it in daily speech? Could this usage go beyond a specific dialect and be used in other dialects, regions, etc.?
Does it really originate from Appalachian English? Why did this usage become popular among other English speakers?
Note: I have already seen a similar question: What are the grammatical rules for use of "these", "those", and "them"?
However, it only says, "ungrammatical," there. This question is specific to this situation only, and there is more to it.