I was in your shoes once, and now going through it again with my grandson. My kids were late talkers. I did not know that. My grandson at 2 years 4 months has one good word, "more" besides Pa Pop, what sounds like dad and mom. gam ma,
One thing you did not mention but I guess the pediatrician MUST have done is refer your son to a ear doctor for a hearing test. Also, did your son have a lot of ear infections? My son did. He had fluid in his ears, and they did not do tubes, as his had ruptured and drained. I think this totally has a lot to do with speach.
If things are not heard prestine, how would you say it; the way you hear it, if you heard it at all...
Put on foam earplugs, how does the world sound now?
My now 24 year old son, with the ear infections, was three and I had him going to a program in the local childrens center. I placed him in a play school setting, with a mom that majored in childhood education and had a daughter herself speech delayed. My son excelled immediatly. At 4 he finally spoke and said a whold sentence. "Mikey, don;t do that. That's not nice" when his older brother picked on him.
From then on I knew he could talk, had a vocabulary, it was now socialization to use it.
My grandson, has a speech therapist come once a week and work on words. Once the words are given, he is picking them right up. This week was please, thankyou, a few others and he is using them. They are clicking, that words meaning and how to use it. The enuciation is still sloppy...old gramma here says it is because he still has the binky in chewing during the day, an ortho one.... and talks through it and that is how words sound to him and he repeats how they sound when HE speaks them.
I am not concerned....with all late talkers, the one between three and four worried as you about kindergarten, he did talk. When he was ready and when he had something to say. Like I said now he is 24....
But, I did work with him and now the grandson with picture cards . a few maybe three a day. HE learned Ball, plane, cat, in that day. But I do not do more then that.
I left the cards with his parents....he just needs to clean up some pronouncing and he is going to be fine.
My friend with the daycare, she did have other issues with her daughter. She had developmental problems of some kind. Great social skills, not autistic, but was always a bit behind the other kids. I have no idea about how school was though, that was 20 years ago.
I would bet, your son, will speak, some day 20 years from now, you will be posting to another Mother of how you had concerns, he was delayed, but did fine once he got going.....
Oh, and turn the TV off if it is on all day. Many studies are now showing more kids delayed speech and relating it to children that the TV is on all day. If the little one is watching Barney and Elmo, he is not talking back to them and interacting like he can with family. Kids need that interaction to say something and be re-enforced with a responce.
Even if it is a red short or blue...to have him respond. Milk or juice, banana or apple....
He will learn the words, and say them back.
I would get a magic drawing board too, inexpensive at Walmart with erasable markers. When he learns a color, a fruit, a word draw a picture of it on the board what he learned that day, use that word that day.
So you are not lableing everything all day giving it a name...but focus on a new word or two a day for the week.
Keep us posted how you are doing. It sounds like he is ready, and it will happen.