I've read that manic phases can change your brain. I imagine that could affect your speech. I had "functional dysarthia" for 6 days recently. Basically couldn't get my words out - I stammered on words and couldn't form complete sentences. Internally I didn't want to talk, or felt like a shouldn't - hard to explain. Went through all sorts of tests and it was deemed it was from my mood disorder. 3 days of dosing myself up with Klonopin and sleeping a ton finally made it go away. Anyway, my point is that the brain affects our mood and extreme moods can affect our brain which can cause real issues. I hope it gets better for you soon.