What does carra barra wirra canna mean in rolf harris's song?

Answer 1

This song is supposed to be a lullaby, and these words are just nonsense sounds that are part of the lullaby the mothers sing to calm their little babies. There is an Irish lullaby that used a similar technique of a made-up but soothing sound, Toorah-loorah, loorah.

Answer 2

The song was actually about Lake Cadibarrawirracanna, which is a lake in far north South Australia. I believe the name (which is Aboriginal or Australian Native) means shining or sparkling on the water. But it is a real place, and not just a lullaby.