This week's New Yorker has an article on by Jake Halpern entitled "Selling the Beat: St. Louis’s Trackboyz break a new act", which includes a some discussion of a St. Louis sound change:
One of their first clients was a young rapper named Cornell Haynes, Jr., later nicknamed Nelly, whom Williams had met at a talent show in a club. Nelly ... was the first St. Louis rapper to break nationally, with "Country Grammar," in 1999. (Nelly also initiated the widespread use of a quirky St. Louis dialect whereby "here" is pronounced "hurr" -- as in Nelly's "Hot in Herre" -- "there" becomes "thurr," and "everybody" is "urr'body.")
This description is intriguing, but it's hard to tell what the pattern really is. In most English dialects, here and there have different vowels -- in the dialect described, do these vowels followed by /r/ merge with one another and also with the final sequence of e.g. burr? In other words, do here, hair and her all merge? And Beer, bear and burr? That's certainly possible, but maybe something else is going on. A merger of the rhymes of here and there might be part of another pattern of mergers, maybe limited to particular words; or maybe they don't merge at all, but instead are just each pronounced differently from the way Halpern expected.
This is probably related to the traditional midland American pronunciations written as "hyar" for here and "whar" for where, as in the lyric
Now what you aimin to do up hyar?
What do ye think you’re gonna find?
Stranger, what did ye say yer name was?
And whar did you say you was gwine?
even though the stereotypical associations in that case are redneck rather than hiphop.
And the fate of everybody raises some other issues entirely. It's pretty common for the syllable written with orthographic "y" to vanish in this word, in versions generally indicated orthographically as ever'body, but to get to urr'body we need to lose another syllable as well. Is this because ever goes pseudopoetically to e'er and then e'er, like there, changes its vowel to what Halpern writes as "urr"? More facts are needed.
I hope that everyone can also start to see, at this point, why the International Phonetic Alphabet was invented.
I'm not sure whether the "quirky St. Louis dialect" that Halpern mentions is covered in Chapter 19 of the forthcoming Atlas of North American English. The online version of Chapter 11 does discuss some vowel mergers before /r/, just not the same ones:
Posted by Mark Liberman at April 1, 2004 09:23 AMA second distinctive Midland city is St. Louis... Its most distinctive traditional feature is a merger of /ahr/ in car, are, far with /ohr/ in corps, or, for, while /owr/ in core, ore, four remains distinct. Though this merger is stereotyped and in recession, it is still strong enough to act as a defining feature of the St. Louis dialect... At the same time, St. Louis is undergoing a massive shift towards the pattern of the Inland North, including the Northern Cities Shift.