The songs I learned in childhood I mostly learned at home, either from my mother or from Burl Ives's records & radio program "Wayfaring Stranger". I started learning songs when I was 2, and knew dozens of them before I went to school at all.

When I was in elementary school (Beverly Hills, CA, 1940s) we had a singing class, but in it, as far as I can remember, we learned no songs that anybody else has ever heard -- they were insipid things from a book compiled for the purpose:

The ants go scouting thru the grass.
They hunt about as on they pass.
If they should march across a worm,
They tickle him and make him squirm.

Some of them, also, we learned from 78-rpm records that were so worn as to be almost unintelligible. The teacher would play the record, and a child who thought he or she understood a scrap would raise his or her hand & offer it, whereupon, if it was right, the teacher would write it on the blackboard. After a few playings, the whole text was assembled by this joint effort, and of course by then we had heard the tune enough times that we could sing it.

One autumn for a couple of months, I think in the 6th grade, I was in North Bennington, VT, instead. The singing there was much more advanced, consisting of hymns & the like sung in parts. I had never heard anything like it before, and it made a strong impression on me.

High school was something else. I went to Putney School, a private school in Vermont, where (it seems to me now) one was almost never out of earshot of someone singing or playing something. Students were not allowed to have radios or phonographs! There were an orchestra & a chorus that did classical music (Bach was king), and the whole school sang together every Friday evening -- classical, folk, Gilber & Sullivan, all kinds of things. On top of that, there was a vigorous folk tradition -- students learned songs, and how to play the guitar & banjo, from other students. I learned many songs there, and during that time also began to learn songs out of books. One of my favorite haunts in those days was the New York Public Library, and I still have song texts that I copied there.