Like the infinite monkeys typing Shakespeare, but with audio instead.
If there was a program that created a series of sounds at random intervals, pitches, amplitudes, etc., how long would it take to produce an output that sounds like music, some sort of recognisable recording (e.g. a bell ring, a dog barking), or perhaps even a human voice?
About the same as as it would take to find you phone number, or any other given sequence in Pi
The minimal sequence of bits required to produce a sound of a voice recognizably saying something is many many many many orders of magnitude greater than a phone number.