C.B.
I would have to say no, it is not a concern yet. My 2-year old daughter has always been advanced in many area's transitioning to new things with little difficulty. She didn't really want to start waving or saying anything until she got closer to 1. It started snowballing within a few months of her turning 1 and she is now talking all the time, singing many songs including her ABC's.
Have faith and keep working with him. He will do just fine
Catherine Benns