This morning Drew, (I think that's a picture of him), was sitting in my lap and he leaned over the arm of the chair and looked at Jack on the floor and said "Dja". Did he just say, 'Jack'?
I decided to test it again so I asked him who this was as I pointed at his brother and he said "Dja".
Later I had both in my lap and ask him again who this was and this time he said "Dja - ka". He didn't repeat it for Robin when she came down and Jack couldn't say anything close to 'Drew".