We live embedded in a web of sound. Sound is the vibration of the world around us. Hearing is the first of our senses to develop: sound is our first sensory connection with the world. Hearing is more deeply connected to the body's immediate reflexive survival mechanism than is sight. Sound reflects movement in our world, sound warns of danger. Sound can locate things we can't see: it operates round corners: a hungry sabre-tooth on the prowl or you mobile phone fallen down behind the desk.
Among humans and other animals, sound carries communication. Animals have a wide vaiety of sounds, from stamping to vocalised cries to other non-vocal resonance-based sounds like bird tweets. Within a species or community) any particular sound will invoke a particular response. 'Alarm-calls' are a common example. Responses to these sounds are normally 'hard-wired' into an animal's brain: Like 'When you hear this sound, run away...'. In humans, these basic communication sounds are mostly in the form of pitched cries. Think of noises of surprise, fear, sadness and so on. But us humans have a consciousness that operates on a logical and abstract level and we have added the additional channel of language on top of our earlier channel of pitched cries and gestures. Language carries meaning to the logical part of the brain. Pitched cries carry feelings and calls to action to the core of the nervous system.
The power of singing has been amply demonstrated over human history by its ubiquity and persistence as a human cultural artifact.