What is it? Why do the French know the tune (I assume this has to do with the cultural exchange between the two neighboring countries)? What are the words to it?
The song is a German folk tune called “Soldier Boy,” as familiar to Europeans as Frere Jacques (but not in the US, apparently). I don’t know what the lyrics say but the singer later became Mrs. Kubrick, who to this day maintains the Stanley Kubrick web site.