Sometimes contemporary speakers pronounce their name a certain way in
order for others to spell it correctly. For example, my maiden name is
Mueller (umlaut u, of course). Many families pronounce it as Miller,
and everyone in the community knows to spell it Mueller.
In our community, though, we had families whose names were Miller,
Muller and Mueller. In order for our name to be spelled correctly by
those who heard it, we pronounced it Mueller, as in Mule - er.
In the other thread:
My mother who learned German in the US from her parents and grandparents
who were from east of the Oder, could not understand the speech of her
in-laws, who were from the Hannover area.