All I can tell you is I have had these issues as well for several months. My tongue/roof of mouth would burn or have numbness. Then my mouth was really dry and I became really self conscious of my speech. I don't know if I would call what I was doing as slurring but certainly messing up many words...and some syllables would sound funny to me. When my mind is off of it, and I'm not anxious...I'm fine. The more you worry about it, the worse it gets. If this doesn't improve for you, I would get it looked at but anxiety can certainly cause these types of symptoms.