"Primarily Mandarin speakers I have known were taught, and believed, that the "dialects" were basically the same as Mandarin, just with different pronunciation."
I am going to take a guess that you do not know many mandarin speakers?
if you did, you would know this is utter nonsense.
My ex speaks English/Mandarin/Cantonese. She is well aware these are not "different pronunciations".
Her Cousin speaks Mandarin and Fuzhou dialect. Once we were all out and he bumped into a friend from Fuzhou and they started talking. I asked the ex to translate as I often did, and she turned to me and said she's in the same position as I am, she can't understand any of it.
It isn't a "pronunciation" issue, or she would have been able to guess some of what was being said.
Most people who are fluent in more than one sinitic language know the whole notion is bollocks. But there are plenty of Chinese who know only Mandarin; many of them entertain, and espouse, falsehoods about what they call dialects and their relationship with Mandarin. You see some of them posting such falsehoods in this very thread, and even insisting after they have been corrected.
What is amazing to me is people who know Mandarin and one or more "dialects" yet still promote the falsehoods. George Orwell called this "doublethink".
I am going to take a guess that you do not know many mandarin speakers? if you did, you would know this is utter nonsense.
My ex speaks English/Mandarin/Cantonese. She is well aware these are not "different pronunciations".
Her Cousin speaks Mandarin and Fuzhou dialect. Once we were all out and he bumped into a friend from Fuzhou and they started talking. I asked the ex to translate as I often did, and she turned to me and said she's in the same position as I am, she can't understand any of it.
It isn't a "pronunciation" issue, or she would have been able to guess some of what was being said.