So I found this website about infant hearing and thought it was interesting to see where Luca falls on the chart. A 3-6 month old should be:

* Reacts to your voice? Luca reacts best when he see your face and can watch your
expressions.

* Starts to repeat sounds like “ah,” “da” or “m-m-m”? Luca says "ah", but so far
we haven't go to the "da" or "m-m-m"
* Likes toys that make noises or play music? Yes, he started laughing so hard today
at a toy that has a lot of musical buttons, and liked most the duck sounds.

We go up to Children's on Friday to meet with the specialist team.