I was trying to find some sites where they discussed music in various cultures both past and present. I am curious as to the subject matter various cultures actually sang about.
The Alan Lomax Collection has recordings of songs from the rural south in the 1930s.
The term of art for what you want is ethnomusicology. I’d start with the various external links from the wiki article. Or you can jump straight to the links from the Society of Ethnomusicology’s site for archives and collections.
Alan Lomax traveled the world after his song collecting in the USA (often with his father & his brother). Here’s a selection.