We have really noticed recently my DS holds onto the ends of his words and elongates them. For example he will say 'are you pumping up the ty-reeeees (tyres)' or 'are we are going to see le-oooo' (Leo) or 'thats really funny mum-myyyyy' and the final sound will go up. He also doesn't pronounce his R's yet either.
I've noticed in contrast to his friends he sounds quite different and it's pronounced enough for other people (adults) to sometimes say it back in a bit of a mocking way. DH and I have asked him to repeat the same sentence back to us when he does it without exaggerating and going up at the end and he can do it. But not in the moment or if he is excited only if he concentrates on it.
AIBU to think this is something to look into? Any SALTS or anyone with experience of similar able to advise?