Is this normal speech for a 3.8 year old boy?

[Toastmonster]

I constantly worry about my son as I compare way too much to other children of similar ages. I feel his speech is behind but not sure if it is, how do yours compare?

Can count to 30
Knows all the alphabet and can recognise all the letters
Mainly talks in 2-3 word sentences, 'juice please mummy' but have heard him say 'we go park, I get my shoes on'
Can sing songs but only from memory

I feel he understands most of what I say and does follow direction (when he wants to)

But he does repeat things alot, from tv shows, occasionally what I'm saying to him (in a mocking tone) - I've read that this is bad by also quite normal with a speech delay)

He doesn't go to preschool until September this year so will this help and has the fact that he hasn't gone hindered his speech? Do they catch up? Any suggestions please?

Are you in the uk? My DD is the same age and starts full time school in September! As all children of the same age in England.
His counting and letter recognition sounds good.
I would say I might expect more complex sentences in a child of his age.
My daughter talks pretty much as I would. Sometimes misusing words and her pronunciation isn't always correct -she can't say certain sounds very well.
Her speech has always been good and developed early and fast.
They are all different and if he's not starting school or another year I wouldn't worry too much.

If you are concerned then I'm a firm believer in acting on the concerns and the earlier the better as often getting the process going can take some time. To give you an idea, I'm not in the uk and it's quicker here, but it's taken 9 months to get my Ds diagnosed with a language disorder. In the uk we once waited 18 months for some occupational therapy.
Go to your gp and ask for a referral for a hearing test, inc a test for glue ear. The need to measure the level of any fluid in your Ds ears.
Also ask for a referral to a speech and language therapist and have him assessed.
If there is an issue all the research shows that early intervention leads to the best outcomes for the child.
Don't let them put you off!

I am in the UK, he'll be 4 second week of September. He had his hearing done about 3 months ago and all came back as fine. I just don't know if it's me worrying too much or if other children are at this level and I only notice the ones that are good at speaking. Any tips for helping him? I always leave a pause to prompt a response, try and talk lots to him, point things out, etc

I think he's within the normal spectrum. Mine can't count to 30 (never tried) or tell his colours but can talk for England.

Well my 23m old can say all of that except only count to about 10.
She has over 500 words.
I havent found not going to nursery has affected her language.
Just comment and encourage longer sentences.
He will be going to nursery from september you will be able to see then how he compares to others and speak to the teachers.

What OP describes is very advanced compared to my kids at same age (normal or higher achievers in school).
3 of mine had speech delay, too.

Thanks everyone, it really does help. He knows loads of words, almost all I would say, all his colours, shapes etc, it's just the putting together of sentences I think he's finding difficult. So if he says 'juice please mummy' should I say 'please can I have some juice mummy' instead of just getting it for him?

I wouldn't correct him as such.
Perhaps just model good use of language.
So instead of just replying "yes" reply saying "yes, I can get you some juice"
Or similar!
It will come.