My elementary school (California, 1940s) had a remarkably effective method of teaching children songs. It consisted in playing 78s that were so old & worn that the words were almost unintelligible. The teacher would start the record, and if you thought you understood a word or phrase, you raised your hand and suggested it. If you were right, the teacher wrote it on the blackboard. After the record had been played enough times for the whole song to be guessed, everybody had learned it.