Sometimes I see and hear parents still encouraging four year olds to use baby talk. I met a mom just last week who was talking to her four-year-old son and she reverted to using his language. She answered him by saying things such as, "Hims a good boy," and "Before night-night time, I'll give you some snug-snugs."
Instead of correcting the child's grammatical errors, she encouraged them. The child has no idea what he's saying will make little sense to anyone outside the family because his mother encouraged him to use baby talk.
Although baby talk has its place, it's best left in the infant and toddler stages. When parents use baby talk, it can help kids learn about language and speech. However, once kids begin talking in full sentences, encouraging them to continue to use baby talk isn't likely to be helpful.
Sometimes parents may use baby talk with older kids because they are bothered by the fact that their little one is growing up. They may think it's cute and they may feel good that their child is still "little." However, it's not likely to turn out well when that child enters school and still talks like a two-year-old.
If you've got a child who uses baby talk, by all means, don't encourage it further. If you answer baby talk by talking back with baby talk, it will encourage your child to continue it. It also won't help your child learn appropriate language skills.
Check out these 5 Ways to Respond When a Child Uses Baby Talk to learn more.