Most States, has a "free" program for assessments and speech therapy.
Its usually under the Early Childhood Intervention or Prevention" type programs, for children 0-3 years old.
Try research it for your State, or do a Google Search.
Now, my son, since 19 months old had a Speech Therapist. He was late in talking. He benefited a LOT by this program and loved it. They do an overall developmental assessment and evaluation, and see where your child needs help or if there are developmental problems.
They come to your home and do everything. Free.
Its really great.
I did not have to go through the Pediatrician to get services. I just called them directly. Then I told my Pediatrician just to keep them updated. At my son's 18 month check-up, they suggested it, for the services.
And yes, early prevention is good. Sure, kids will talk when they talk. But at the same time, if you can get these services to ally your concerns, or to help your child, why not? Its free.
Then, you will know for sure, from a Professional, any information and if your son needs help.
Its not hard. My son, was just 'late' in talking. His assessment showed that he was even advanced in several developmental areas... but just needed help and encouragement in talking.... and it DID help a lot and my son really enjoyed it.
There are many technical aspects to talking.. .and at certain ages, certain "sounds" are mastered... because it has to do with the mouth / tongue/ throat coordination as well. And there are "front of t he mouth" sounds/words and "back of the throat" sounds and words, for example. AND, the articulation of words, is also something that is mastered at different ages. So the Speech Therapist will explain this.
try looking into your State's free early childhood intervention programs.
All the best,
Susan