nonsense refrain in songs, probably from Old English la, a common exclamation; but la-la is imitative of babbling speech in many languages (cf. Greek lalage "babble, prattle," Sanskrit lalalla "imitation of stammering" Latin lallare "to sing to sleep, lull," German lallen "to stammer," Lithuanian laluoti "to stammer").
Meanwhile, returning from la-la land to our regularly scheduled program, 86 people died in the United States today from gunfire.
When his literary ancestors attempted to conquer la-la Land, they were rebuffed, rewritten, or humiliated.
He was leaning his hands on his stick and she reached out and took hold of it and says 'la-la!'
"It becomes us to take care of the pence now," she would say, and go on with her everlasting whistling, la-la.
And I says 'see the nice gentleman's stick,' and she gurgles 'la-la!'
"Tra-la la la-la-la-la, la-la la," he sang, snapping his fingers.