K.,
No matter what others think, you are doing the best thing that you can for your son. Talking to him daily and telling him what you are doing or pointing out little things will make it easier for him to learn new things when he gets older. When I had my first two children, I worried all the time about what other people thought of how I interacted with her, so I didnt when we were in public. Now that I am on number three, I have talked to her everyday just like I am talking to an adult. Explaining things to her and giving her a chance to "answer". She started using real words way before the others did, and others could understand her too! I attribute this to me talking to her every day from day one.
Dont worry about what the people around you think! If you hear them comment about it, just tell them that you are teaching your child to pay attention to detail and that he may be a doctor (who needs to pay attention to that little detail) when he grows up. Teaching him now that words have meaning is the greatest thing that you can do for him! =)