we can all experience positive and negative emotions eg. Happy and Sad. The ability to understand and express these emotions starts developing at birth.
By 12 months typically developing babies can read your face to get an understanding of what you are feeling.
Most young children start to use words to express feelings although you might see tantrum when their feelings are too big for their words.
throughout childhood and adolescence children continue building empathy . They also build skills to manage their emotions and recognise and respond to other peoples feelings.