I think that Jonathan may, just possibly, be connecting the sounds “dadada” to the person Daddy. Yesterday I was changing his diaper, and Gabe came over to smile and say hello to him. Then as Gabe turned away and started to leave the room, Jonathan started crying and saying “dadada”. Of itself, that wouldn’t be very convincing…except that when Gabe turned around and came back, Jonathan immediately stopped crying and smiled.
Ever since Jonathan has been making the “dada” sound, we’ve been actively working to connect the sound with the person. Maybe it is working?