3 year old shouting or screaming

Just writing to see if anyone has any advice about this my 3 year old has recently started shouting and screaming really loudly most of the day mainly when he’s in the house but it’s really hard to know why. He has limited communication but can make most requests and when he’s shouting it’s not in direct response to anything. We had a baby 8 weeks ago and he was fine but since Christmas definitely shouting more. He has also been potty training but is doing really well with this. I can’t work out the trigger but also don’t know the right way to tackle it as it’s a lot for us when he’s shouting all day any advice would be welcome x