There are many children who suffer from speech impediments. These impediments usually aren't caused by anything that a parent has done wrong, instead, it is just a problem with development that needs to be corrected. Here are a couple common speech impediments and what you can do to treat it.
Saying The R Sound
One of the most common speech impediments is saying the R sound. It affects many children and usually it takes the child till they are about 8 to really learn how to say it. This is why you shouldn't worry too much if your young child is struggling to say the R sound correctly. Rather that start them in therapy at 4 years old for it, do things at home to encourage them to say it correctly.
Once, the child get's closer to 8 years old and still has a hard time with the R sound, you should consider therapy. With R, the child needs to learn how to place their tongue. Start early by teaching the child to roll their tongue back into their mouth. This can be paired with having the child spread their lips into a smile form and roll the R at the same time. Do this and practice with your child while say words with R at different positions until they can say it. If you still have problems consider therapy.
Saying The L Sound
Another common troubling sound is the L sound. Many children will substitute the Y sound for the L sound. So instead of saying "I Like" they will say "I Yike." The L sounds can be a simple one to fix if you sit down with the child and help them to see the difference. Have the child stick their tongue out every time they say the letter L. It may be very exaggerated at the first, and that is fine. Usually they should master the L sound by the time they are about 5-6.
Saying the TH Sound
Lastly, you might notice that your child is having a hard time saying the TH sound. This commonly get's replaced with the F sound, so instead of saying "mouth" they say "mouf." Once again this all has to do with the placement of the tongue. You should focus on having the child stick their tongue out when they talk and with this sound you kind of bite the tongue. Have the child say the sound in the mirror until they can see the different. This takes until 6-8 to master.
If your child has a hard time saying these sounds, consider getting speech therapy, such as at Daniel Island Speech Therapy.