Writ by hand an' seal't wit terbaccy joos
The strip was created in 1919 by Billy DeBeck, and he hired Fred Lasswell a few years later to do the lettering. It was Lasswell who created much of the hillbilly language that actually made its way into common American vernacular.
In his biography he says he "scoured used bookshops...for books on hill folklore." He would note the language and use it in the strip.
The Biography claims he concocted "Bodacious Idjit" on his own, but it's really from the 1888 book "The Story of Keedon Bluffs" by Charles Egbert Craddock, who wrote a number of hill folk oriented books.