My 3 yr old has a pretty good size vocabulary however he does not say the first letter or sound of the following letter: C, CH, G, J, K, S, T, V and Z. This makes communication between unfamiliar people difficult as they can not understand him. Oddly when we "play" sound repeating his is able to make the sounds, but when they are at the beginning (only) of a known word, he omits it? Is this something other people have encountered? What did you do to correct this or did it resolve itself. Half of me says he is just three, and since it only affects the sound at the beginning of a word, I am not sure how to proceed. Thanks