You should be, asking your Pediatrician.
Get a professional's opinion.
You said you had his 2 year check up. But did you ask the Pediatrician, specifically, about his speech????
Now, my home is a bi-lingual home.
My kids have no trouble with it.
At school they also learn 3 other languages.
Its fine.
They can speak it, understand it when spoken to, read it and write in the languages.
Better than me even.
My son, when he was under 3 years old, did have speech therapy. It was free from our local Early Childhood Intervention organization. But, his was just a speech delay. They do an overall developmental assessment on the child. He was even advanced in some areas for his age. And they said, that our bi-lingual home, was not a problem. Nor the cause, of his speech delay. And he could perfectly understand what was said to him and had no hearing problems.
Currently, and since his speech therapy, my son is the most talkative one in our family. And he has an astounding vocabulary for his age, and a very articulate ability to express himself, for his age. And he still remembers, his speech therapy. Which he LOVED.
Both my kids are tall for their ages. It was never a problem. Size has nothing to do with speech or interaction with others.
My 6 year old son, commonly gets mistaken for an 8 year old.
Boys are naturally also, very physical. Yes, they love to run around. They need to.
Your concern is your son does not talk, much.
So tell your Pediatrician, that.
There would be no harm, in getting him evaluated. Up until 3 years old, it is free through Early Childhood Intervention. For me, I didn't even have to get referred by our Pediatrician. I just called them myself. They come to your home. It is free and totally voluntary.
Speech, it not just about talking.
It requires, mouth coordination. Lips/tongue/throat coordination and making the sounds, of the letters in combination.
Some letters being harder than others, to form and sound out.
And per age, the ability to say... certain letters/sounds, are developed.
Did your son... "babble" as a baby?????
Did he go through that developmental stage?
Babbling, is also, a precursor, to talking.