From the very beginning of time, the Planet Earth was not a silent place. And, as it was increasingly populated by living beings, these quickly learnt that sounds constitute an excellent means of communication.
All communications by sound imply the existence of a message and at least two participants, one who emits it and another who hears it.
When both are of the same species, it is assumed that they will gain some positive benefit from this acoustic signal. But problems may arise when enemies intercept sounds which are not meant for them, and learn to use them against those producing them.
There is a universal code among animal species by means of which they all innately recognise when a call is a threat….when it is an expression of desperation…or when it signifies true fear.
But, without a doubt, the pinnacle of progress in communication through sounds is human language; a combination of pre-established tones capable of transmitting complex messages and sensations..