For your baby, his senses and expressions do all the talking as he is not as adept at speaking as adults. A simple act of touching someone on the face, can have a number of unspoken things behind it. For your baby currently, this is the only form of interaction.
What you need to know
Just like we adults need revert on something we speak, your baby needs to get revert from you too. You can interact with your baby by conversing with him or reciprocating some of his actions, which will certainly make him feel very happy about it.