Physical and language development.
-The child is independent of physical (Physical Independence) more. Walking distance to run. Exploring the environment.
-Children start speaking a Word. Understand the language of gestures and command more. At the age of 2 years, say 2-3 words with meaning.
Development of ideas
The development ideas of Sensori-motor stage 12-18 month period Piaget (Tertiary Circular Reaction) is trial and error (Trail & Error) is interested as a result of its own. Start to understand the perception of external objects, persistence of objects, even when the objects are obscure or hide len out of sight or be moved to another (Object Permanence) 18-24 months, starting with the idea. Imagine having the ability to solve problems with new way, but also as a trial and error style exists.