3 DC all with a posterior tongue tie to different extents.
DC1 we were told she had a tongue tie but it wasn’t severe, she was breastfed and lost 12% of body weight by day 5. She had a really bad latch and would fall asleep during feeding. Ended up formula fed and still struggled with bottles (milk dribbling out). Had her assessed at 4 weeks old and were told it was only classed as borderline but was cut as it was obviously affecting her feeding. She was much better afterwards and far less windy.
DC2 had issues with latch when breastfed but fine on bottles and gained weight fine, which was lucky as she was born at the start of lockdown so they wouldn’t cut tongue ties unless necessary. Hasn’t affected her speech at all though,
DC3 is more obvious, you can see his tongue tie when he laughs. He’s been fine on bottles but again his latch when breastfed wasn't great and it was really painful for me. His hasn’t been cut because he was feeding fine.
I also have a tongue tie, a midwife diagnosed me after I had DC1 and DH asked if it was genetic and she said it can be hereditary. It hasn’t affected my speech, the only thing I ever noticed is I do have a really short tongue, I cant stick it out much at all, but never even knew it was a tongue tie until I was an adult.
From what I’ve gathered they seem to say a posterior tongue tie doesn’t always need cutting as they don’t always affect feeding and speech. But obviously on the speech you can’t know until they’re older. If you’re concerned I would have your DC assessed and see what they say. They will grade it and tell you whether it needs cutting or is borderline or below. You’d probably be better off going private though as the wait times can be quite long.