During the first two years of life, an infant is in the sensory-motor stage of cognitive development, according to the developmental theorist Jean Piaget. Your child explores his environment through sensory (e.g. seeing and hearing) and motor (e.g. sucking and grasping) contact.
By one year, your child will be able to say two or three words with meaning. He may recognise an object and point to it and will be able to understand simple questions.
He starts to develop object permanence, which means that he can make a mental representation of something that is not there. In order to encourage object permanence, show him an object and hide it. Encourage him to look for it.
By fifteen months, a child jabbers loudly and freely and speaks two to six or more recognisable words in correct context. He may be able to understand and obey simple instructions and can make animal sounds. He will be able to know parts of his body, and will fetch and carry things. If shown how to, he may be able to build a tower of two blocks.
By eighteen months, his vocabulary has increased to twenty recognisable words but he should be able to understand many more. He may be able to build a tower of three blocks after demonstration.
What you can do to help:
Talk to your child constantly: describe your actions (such as putting on shoes), refer to different parts of his body and start reading simple stories.
(Ilse Pauw, Health24)