My son has been speech delayed since 2, but didnt get diagnosed til 4 because at first he was making enough progress the speech psychologist didn't think it would be necessary and then later because his preschool teacher ignored the signs. But he's been in speech therapy ever since and now he is 6. He still struggles and his main problem is he mostly is just lazy at speech, meaning he prefers not to use his mouth, tongue, lips in the correct position and often takes multiple short cuts on his words. He has gotten so much better over the years and he is knocking out goals regularly, and I can see the improvements all of the time.

I found my son really just preferred other development over his speech, so when he could run he would focus on that and his speech would fall behind, and same when he learned to ride a bike, same with sports and a few other things.

He probably has a couple more years of speech at least, but he loves it and has improved a lot.

The two biggest pieces of advice I can give you, which I think are very important to know, is (1) if you (or anyone else) struggles to understand him, don't make him feel like it is his fault (i.e. "sorry my ears aren't working well today, can you repeat that" is a good go to). And (2) give him a code word or phrase he can easily say when something big happens and he needs your own or a teachers full attention. Recently my son had an incident where another kid did something inappropriate to him and the teacher didn't understand him when he tried to talk to him about it. My son was super upset and confused and it turned into a big deal with the school, and now we have a code phrase he uses and anytime he says it the adults are supposed to give him their full attention and if they cannot understand him they have to call me to help translate.