developing child's voice

What are the basic requirements needed for children to learn to sing? The physical ability to sing depends on the degree of normal and healthy development of the vocal mechanism (larynx, vocal folds, breathing apparatus), and on one’s neuro-biological ability to process music pitch.
Anyone who has heard a child improvise melodies from the crib knows it is a precious sound. Little ones can babble repetitive songs with pitch accuracy as early as the age of ten months. It’s likely these children have been sung to and/or have heard singing frequently during the pre-birth and early infant years.