Although authentic Montessori programs continue to promote the study of the whole child there's still a need to separate the different developmental aspects in order to aid child observation. Psychologists have separated child development into six categories - physical, intellectal, emotional, language, social, and spiritual.
How a child's body grows and changes is the most obvious development. Physical development begins at birth and continues on throughout childhood. The rate of physical change is not, however, a constant among all children, and this can greatly impact a child's emotional and intellectual development simply by the ways in which others respond to her. For example, if a child is shorter than most children of her age, she may be treated like a much younger child.
Proper development of the emotions is crucial for good self-esteem and self-perception. When a child is in a positive environment in which her emotional needs are met she is free to think and act in the best way she knows how.
Communication or language development begins with a baby's first cry and continues through to learning how to read and write. It also means listening and understanding. This can be seen very clearly by observing a child of two who may use only a hundred words or so but, by the time she is three, has learned over one thousand.
How a child learns to relate to other and becomes a contributing member of a community or group is the aspect of social development. Learning to share, acquiring friends, or having constructive arguments are all vital steps toward becoming a social being.
Finally, the term spiritual development has nothing to do with any religious concept. Rather it is the developmental aspect that allows a child to relate to others in an ethical, moral, and humane fashion. It involves understanding the needs and feelings of others and, later, concern for the needs and fellings of others.