As you know, Joash come from two rather musical parents. And we are perhaps seeing a love of music developing on our son.
I sing with Joash a few time each day. I sing children's Sunday School songs like "Jesus Loves Me," "Praise Him! Praise Him! All You Little Children," and "This Little Light of Mine." If there are any actions to the song, I try to move his arms and hands to mimic the actions. And it never fails that his smiles and coos just start rolling out. This happens too at bed time when Wilbert sings the Dutch bedtime prayer song to Joash. He always starts to coo and smile then.
It is funny because we talk to him all the time and read books and play with him in lots of different ways. But, if you want to bank on getting some coos and smiles, you have to sing. So perhaps a love of music starts young.