Note: I am aware that the two negative elements cancel each other out. for example, "He is not unhappy" means "He is happy". I just want to know "I don’t know nothing" means "I know nothing" or "I know something".
A tutorial on VOA says
... if you told an English teacher, “I don’t know nothing,” the teacher would probably correct you with, “I don’t know anything.” This kind of double negative is taboo in professional and academic situations. Some people see it as a sign of being poorly educated.
I suppose that means the English teachers consider "I don’t know nothing" as "I don’t know anything", the former is a bad version of the latter, though both of them have the same meaning.
An ELU post says
There is no semantic difference between these two:
I know nothing about that.
I don’t know nothin’ about that.
By far, "I don't know nothing" = "I don't anything" = "I know nothing"
An ELL post says (meaning_2)
"I don't know nothing" means "I know something."
Meaning_2 sounds more reasonable though, different sources are conflict with each other.
Could someone please explain this particular sentence?