Hi, a warm welcome to silkysteps
A few factors involve:
The language that is used around the child and how that language is used.
Knowledge, understanding, experiences, the size of vocabulary and fluency used by the child and those around the child.
The opinion and views of others that surround the child.
Interests of the child, Child's family and the setting - how the setting approaches or likes to provide its learning, care and development.
Resources and what's available to support play, learning and discovery.
Socio-economic cirumstances of each child - family, money, access or transport to get places.
Book preview on google -
Intellectual development
Hope this helps, enjoy the site xx