Vowels preceding /r/
(Grand Rapids, Michigan)
My 9 year old son strugged for quite a while to get the /r/ sound, but has finally started getting it. It's still not perfect, but much better and improving. The problem now is the /o/ sound when it precedes /r/. He can say "star" "stare" " stir", etc, but "store" becomes "stir", "four" becomes "fur", "door" becomes "der".
I can find nothing about this specific problem on the Internet and would really appreciate any tips or links to resources.
Thank you for your time.