Two of my children have had speech delays, and both got ST in school with an IEP. I was never that concerned about either of them, although my youngest hasn't advanced in progress as well as his older brother.
If you are concerned about your child, but not sure if you should seek out help, here is a good resource:
If your child is in school, you should talk to their teacher to see if they can be evaluated. You should also discuss your concerns with your pediatrician. One of my boys was able to get some ST when he was a toddler, we just had to go through an evaluation with the county.