I know how much we all love slang, language and dialects. I even recall a conversations from the Sheep Farm event in 2011 where we talked about what kind of dialect someone in Minnesota might use/what accent they have.
I stumbled across this volume, a Dictionary of Americanisms from 1859. Of particular interest is the section on dialects, which has a list of "incorrectly pronounced" words, and includes the places where those pronunciations are found. The author does point out that those pronunciations might be found elsewhere, "for an immigrant from Vermont to Illinois would introduce the provincialism of his native district into his new residence".
Interestingly, the author also considers the terminal "ity" to be American, versus the English "ness", such as in accountability vs. accountableness, as well as the use of "extravagant" terms. And, it includes examples/sources for particular phrases, so one can see them in context.
It's an interesting read on its own, but also if you wanted to refine your 19th century "dialect" with some slang language, or need some help when reading primary sources, this is a good one!https://books.google.com/books?id=W89ZAAAAMAAJ&pg=PR26#v=onepage&q&f=false