I've got 14 month old identical twins (13 adjusted) and they still don't respond to either name 
It's like they can't hear me, yet their recent hearing test was fine. They can definitely hear.
There are many positives (eg. they love music and will copy sounds and actions, they'll clap and wave if asked to), but their social development and actual understanding seems way off where it should be. They don't seem to recognise the name of any objects, mummy/daddy etc. The other areas of their development are fine and they are walking. They're incredibly curious and love exploring and playing with all of their toys, looking at books. There are no sensory, sleep or food issues.
I feel absolutely sick with worry about this, to the point that I'm going to call the GP next week for some help. Can anyone relate?