Quite a large number of children face speech children. It implies that even when a kid is growing up he still talks like a baby. Parents often feel stressed about this issue but trust me; this is not an unusual occurrence. Many parents face similar set of problems but with some adequate steps and practice they have managed to solve this problem. Before you begin to take any step remember one thing, you cannot make your child to talk like a big guy overnight. It will take some time and of course, patience.
Have you observed yourself how you talk back to your child when he talks like a baby? If you talk back to him similarly as you used to when he was a baby then you need to stop this habit right away. Because, this way you are encouraging him to continue his baby talk way. You need to check your response and should probably devise a new strategy. You might think of responding to your baby by saying that, “I am not getting what you are saying. You need to convey in big guy words” or something like that. If you keep doing this for few times, child will get the message and may start trying big words after some time.
You can also sit calmly with the kid and tell him that he is now a grown up boy and should start talking like grown up kids do. There could be several such ways to motivate your child and send across your message. After certain duration, child will definitely get what you want to say and will start talking normally. Just be patient and try out ideas and soon results will be there for you to see.