DS is nearly 4 3/4, and about to start school. I would say he has a very good vocabulary and grammar for his age (though that's just my guess), and definitely no hearing problems (ears like a bat!). However I have noticed lately that he still has several sounds he can't pronounce properly at all, and every so often he will really struggle to get me to understand something he's saying. Obviously this is worse with other people too; DH and I can understand him better as we're used to it.
I'm not expecting perfect pronunciation at this age of course, but am not really sure what's normal, and the reason I'm asking is because DS now gets very frustrated and upset if I can't understand what he's trying to tell me. Although I try not to make an issue of it, he is sometimes almost in tears and tells me "but Mummy you are not using your ears properly", or "it's not my fault, it's just my voice!" while looking heartbroken, and I really feel for him!
The sounds he struggles with most are c, g, ch although there are probably a few others too. For example, "caught" sounds more like "taught", "grass" is more like "srass" and he struggled a lot with "choose".
Is this normal for his age, and is there anything I can do to help him become clearer without making him more self-conscious about it? Thank you!