I have had speech problems and was wondering the same thing. Some days others can't understand a thing I say.
When I saw the first Lyme doc last year, and i told him about
it, he said the same thing as my second Lyme doc. He said "I don't like that". Apparently it's when the spirochetes go "deep". One doc said "I can't bring it back, but I'll keep it from getting worse". PS it improved after 6 months of rocephin. But, long story short, I had to pull the PICC and it really got worse after a few weeks while I was gearing up for another PICC. I am back on rocephin and hoping I will sound like myself again in the fall. I feel like my tongue is too big for my mouth, and my muscles in my mouth aren't really working too well (like the rest of my body).
It's definitely worse at night, and considerably worse if i eat gluten. Between that and the severe balance issues (and plenty more) people think I am drunk all time!
I would welcome other people's input. Not that I wish this bizarre symptom on anyone, but it's comforting to know I am not alone with this problem.
Hang in there because it can improve. It's a long haul...