I don't have a Newf but I did try to look this up on the internet for you... Â
I found a couple things that said that purebred Newfs with black or purple on their tongues have a recessive ticking gene (the gene that causes the black tick marks on a Landseer Newfie). There may or may not be black tick marks elsewhere on the dog as well, but they don't show up on the already black fur, just on the tongue...
Take it with a grain of salt, as we all know anyone can post anything on the Internet and be considered an expert. Since I am the farthest thing from an expert, I have no clue if this is true or not. Maybe some can confirm or deny, and then we will BOTH know! Â