How to know that my baby is responding to sounds and new colours.

Abhilasha Paul is expert in this

Hi moon. Please notice the following things
1. Does the baby look at you when you are talking to baby.
2. Does the eye widen or does the body jerk when there is loud sound.
3. Does the child wake up on loud sounds in the environment. If yes then all good. If no then you may have to go in for some tests.
Did the child undergo new born hearing screening.??

Recognition of colours a eye specialist will be able to guide better.