Both the ability to produce these vocalizations and the ability to understand them may be genetically encoded, as may be seen from the first instant of birth with a baby's lusty crying on emerging from the womb. Babies are wonderful vocalizers. Their cries are penetrating, and they are able to continue for hours without getting hoarse or damaging their vocal apparatus. Their breath support system is perfect and natural. Sounds of pleasure from babies are likewise directly communicative of joy to adults who are in contact with them.
Adults too have a remarkable repertoire of elementary vocalization forms, all tied to affect.
Involuntary shouts of surprise, anger or fear are as penetrating and physically efficiently produced as a baby's crying. Sounds of pleasure are equally involuntary on the part of the producers and recognizable on the part of hearers. Singing is built on this human system of vocalizations. It is able to produce an emotional response in listeners precisely because listeners are genetically programmed to respond to the acoustic properties of song, as they respond to other pre-linguistic vocalizations, but in a more directed and differentiated fashion. Whereas response to elemental cries and vocalizations may be limited and diffuse, response to singing is directed and nuanced.