What appears to be a hidden tongue frenulum

Hi all,

My 5 year old was very slow to start talking, and even now has a big problem with pronouncing his c/k/g's

He's under speech therapy, but today I read an article on tongue tie in children and checked under his tongue to find he has no visible frenulum.

He doesn't appear to have a posterior tongue tie though.

Has anyone any experience with anything like this? Thought I'd post here before contacting the health visitor tomorrow.

Tia

Emma