Perhaps it should be pointed out to Waverly that colloquialisms and slang are quickly picked up by ESL speakers, and used on the job and in everyday speech. They learn that 'book English' singles them out from fellow workers if they hope to get along in jobs below professional level.

Ain't has been used in common speech for over 300 years, and will continue to be used, despite complaints by those who insist on proper English, whatever that is.
Certainly 'correct' English should never be invoked in judgement on folk song.

The remarks of H. L. Mencken in his classic, "The American Language, are as applicable today, if not more so, than they were when he wrote them in the 1930's.

"For many years the indefatigable schoolmarm has been trying to put down the American vulgate, but with very little success. At great pains she teaches her pupils the rules of what she conceives to be correct English, but the moment they get beyond reach of her constabulary ear they revert to the looser and more natural speech-habits of home and work-place."..........
Speaking of professional students of American English, Mencken says "In particular, they have failed to make an adequate investigation of the folk-speech she tries to combat ......"

The language is constantly changing through slang that, as Mencken said, "appears from nowhere, has its brief day, and then vanishes."
Some remains within a group, some spreads to a larger segment of the public. Many of us, for example, are lost when faced with the speech of urban African-American children, although those interested in the evolution of popular music may pick up a bare bones understanding of it.

Bam da lam may have had meaning for Lead Belly and his 'associates'.
Bam by itself has several meanings, depending on the group and context.
BAM, broad-assed Marine, Marine Corps slang, as an appellation for female marines, but has spread to the military as a whole.
Bam for pills (medication or drugs) is not uncommon. I have heard it here in Canada.
In the 19th c. bam was commonly used for to mislead, or to hoax, appearing in literature (Halliburton, "The Clockmaker," 1838). This definition is uncommon now.
See Lighter, "Historical Dictionary of American Slang."

Maybe some day schoolmarm will be able to sing "I seen the light and the truth is mine, Ya ain't welcome here." And the songs with 'done gone' in the title are many.

I haven't read it myself, but I wonder if Azizi knows the book by Alice Randall (Af-Am), "The Wind Done Gone Home," Houghton-Mifflin?