KP- one thing about “iron” and “nuclear” is that “iron” IS pronounced “i-earn” not “i-run” (at least according to the
OED) while “nuclear” is supposed to be “new-clear.”
pluto - now, i’d hate to label one accent as being “spectacularly” uneducated and another as being “cultured,” but i understand what you mean. certain accents are more associated with the working classes and certain ones are associated with the upper classes. when i hear scottish english, it sounds so beautiful and musical to my ears, but other can’t stand the sound of it.
when i speak rapidly, and more relaxed, my chicago accent comes out. the "th"s turn to "d"s and "t"s, my “str” start sounding like "Shtr"s. And all the vowels turn to schwas.
“Yeah, I live over dare on forty-turd shtreet. just go uptadaendada alley and turn left.” and i certainly wouldn’t consider myself uneducated. i grew up in a working class neighborhood, composed of Poles, czechs, irish, and mexicans. hence, i assume, this is why "th"s are turned into "d"s and "t"s in working-class accents, because these sounds are not native to most european languages.
I was surprised a couple years ago when I found out that
“folk” was pronounced “FOKE.” All these years I had been pronouncing the “l” assuming that this “foke” pron. was some local accent. Imagine my disbelief. I still can’t say “foke” without it sounding weird to me.