I know a 2 year old albino burmese python that goes through the motion of flicking his tongue, and you can see it move under his jaw, but it's never (ever) flicked out of his mouth. He's in perfect health and does not show other mouth symptoms such as drooling or bubbling that could be associated with various mouth problems. I cannot find any real information, scientific or anecdotal, to definitively assume it's a fused, short, deformed or otherwise tongue. It's not causing the snake any problems, and as far as I know he eats well, but because he doesn't fully utilize his sense of smell, he is conditioned to eat f/t via touch, which could become more difficult as he gains size. This is mostly an endeavor of curiosity.
He was from a surprise clutch from a rescued animal who slugged out all but 8 eggs and as far as I know only two hatched and his sibling did not have any problems. His head scales and eyes are very slightly cockeyed so I wouldn't be surprised if it's overall a birth/incubation/inbreeding defect, but his owner says his tongue appears normal, just doesn't come out. We were simply looking for some information on the matter. Because the animal is in ideal health, there was really no need to take him to a vet to discuss it so please don't suggest that.
Thank you herp veterans for any information you can share!