ROFL !
At first I was wondering how it was possible to have an Aboriginal man bull-roaring in front of both a camera and his wife...
Then, ok, it's an advert !
The bull-roarer is one of the most powerful and secret-sacred object amongst the Aboriginal people (along with the lethal pointing-bones).
It is exclusively possessed, used and even seen by initiated men of high degree.
Using it as a "bush telephone" is a legend (same goes with the didgeridoo).
It was mainly used during initiation ceremonies, at night, after having told frightening stories to the young men in initiation and leaving them in the darkness alone... it was supposed to be the voice of a dreadful spirit, meant to make them sh!t in their pants (or loincloth).
But it was (is) not only a lure but was (is) also believed to
really be animated by a higher force/spirit.
It may be compared to a telephone, but not for man-to-man communication, rather for man-to-spiritworld.