H.C.
There is an option of having him evaluated by a program called the regional center to see if he needs a little speech assistants. or wait till he is three go to your local school and registar him and request a evaluation through the speech program. if you are truely worried this will but your mind to ease.
Every child is different and does things at different speeds but this is alway a better be safe then sorry approch you have nothing to loss only to gain.
hope it all works out.