At this age, your child loves to speak and communicate. So those who speak more he would respond to them and look at them continuously. As a parent, you need to speak up more, so that your child attends and learns new and innovative things. Encourage him to speak which would enhance language, cognitive mental abilities to learn new things.
What you need to know
At this age his cognitive skills are at its best. The more you speak the more attention he will pay to it and ultimately learn more. Children at this age understands visuals and voices. So your child likes to respond to whoever is speaking and understand what the person is saying. So he maintains complete attention on the speaker.
What you can do
Since, your baby is closely pays attention to your voice, tone and pitch, you can start speaking slowly to make sure he makes the most of it. He will even observe your lips movements, so by talking slowly, you are helping your baby to capture the essence of the language itself!