I also wrote about it. It’s connected to „infantile swallowing”. Seems like 3-4 year old child should change tongue placement but if you have alergy and runny n

I also wrote about it. It’s connected to „infantile swallowing”. Seems like 3-4 year old child should change tongue placement but if you have alergy and runny nose then you might never learn it. I suspect that for me it switched back later as I was very good in long distance running as kid and after one time beeing sick I never recovered to my previous form. It never occured to me that it was tongue placement :(