"Lazy Tongue" Diagnosis

When I was younger I was told I had a "lazy tongue". I went to a speech therapist for a while and had to practice saying words with few syllables in them e.g hip-po-pot-a-mus.

However as I've grown older it has become a struggle. People say I mumble some times and is hard to understand me sometimes.

When I read in my head, the words feel fine but when I go to say them out loud, I get jumbled and mumble. It's hard having to always try and concentrate on how I say words.

As "lazy tongue" is not a proper diagnosis, what would be the problem? And how would I help resolve it?