Is this normal? Toddler speech

[TickleMeEmo]

Sorry if I sound a bit over anxious, I don’t have any experience of toddlers or child speech development and my husband and MiL think I’m being over worried.
Over the past couple of months my 21 month old’s words seemed to have really exploded and he had even started putting strings of 2-3 words together to make basic sentences i.e “mummy sit down” “doggy come back” “daddy’s car gone”
However the past week or so he seems to be mispronouncing words that he could previously pronounce no problem and shortening words he was saying in full... for example all his H words he is now putting a C in front of (Cand for Hand, Cat for Hat, Corse for Horse etc) apple is now app, come sit down has became “seat” etc
Is this just a phase or should I be worried?
His understanding seems fine and otherwise I have no worries.

If it's only been a week, I'm sure it's nothing to worry about OP. It might be worth doing the m-Chat

I noticed this in my DS when he started using more words. I put it down to the fact he was concentrating on using the new words so wasn't concentrating as much on pronouncing things properly. His pronunciation gradually got better and is now doing fine verbal communication wise at 3. I don't think it's anything to worry about.

Thanks for your replies, @ParadiseLaundry that seems to be what DH is saying, that he’s just exploring different sounds and responses and focusing on so many new things all at once. I think I’m just over thinking everything at the moment as we’re about to have DC2 in 6 weeks and I’m super nervous about how it will affect DS 😬 I never used to be such a worrier before kids 😳