Here are the milestones of a child development:
4 TO 6 WEEKS: First smile (usually during a feeding)
6 TO 9 MONTHS: Baby sits up on own and babbles
9 MONTHS TO 1 YEAR: Baby crawls and stands; recognizes own name when spoken; says a few words
8 TO 14 MONTHS: First steps and many words
18 MONTHS ON: Toddler builds up more words, sentences, meanings
3 YEARS: Average age when toilet training begins, as a child begins to understand the concept, to imitate adults, and to respond to simple instructions
4 YEARS: Memory matures just as preschool often begins
5 YEARS: Language and learning skills build, and abstract thinking begins to develop; the first day of kindergarten approaches
These developmental milestones are matched by growth of the brain as an organ. In the first year, your baby’s brain triples in weight. By the end of the second, your toddler’s brain weighs three quarters that of an adult’s. The brain’s activity increases with its weight. The metabolism of a baby’s brain, as measured by how much blood sugar it uses, builds steadily from birth until the age of 3.
In most children, the progression from hearing to speaking to reading and finally to writing goes without any difficulty. Left brain typically controls language, which consist of speaking and reading skills.