DS2 turned 4 back in the autumn, starts school this coming September. He is very confident, sociable and articulate, and most of his speech is very clear and easily understood. However, he is still pronouncing various words in quite a babyish manner (i.e. 'dat' and 'dis' for 'that' and 'this') and has his own take on some other words (for example, 'laspberry' for 'raspberry'; he is an Abney and Teal fan, but always pronounces 'Abney' as 'Avney' and 'Neep' as 'Meep').
Is this something he's likely to just grow out of as he gets older, or might there come a point where he'd require speech therapy?