Language Delay 4-5 yr old

My 4.5yr old son who is full of energy with a severe language delay can say what he wants e.g.

I want ice cream please', let's go outside, I want to watch Barney etc, it's mine, it's my turn,

describe objects: it's wet, cold, hot, colours, knows multiple people and calls them by name, greets hello aunty hi bye mummy without prompting

Describes what's happening: daddy is eating rice, daddy's car gone, my apple fall down

Uses exclamations yay! Grandma is back, oh no, ouch my boo boo leg, hurray, I got it!

Asks questions like where's playdough? Where's daddy? Where's cat?

He is very friendly and plays with and has friends in nursery but with minimal language so mostly non speaking games and he loses interest easily.

He is not conversational or speaking in longer sentences or answering most questions.

He has been in speech therapy for one year. Recently started occupational therapy to improve focus, attention and hyperactivity.

Are there any other mothers out there currently in a similar situation or was previously in a similar situation.

What more are you doing or have you done to help?

When did your child become conversational and speak in sentences?