"You want to see if the child can protrude the tongue forward beyond the teeth." Doctor Stewart, Otorhinolaryngologist-in-chief at New York Presbyterian Hospital, reviews some common signs that a child may have tongue tie, including problems with breast feeding.
Being tongue tied isn't serious though. Kids will mature, and will find other ways to pronounce words. It doesn't affect one's personal health. But it does get in the way of stuff like kissing, and it does hurt once in a while.
RachaelDineen 3 months ago