I don't know anything about dyslexia, but your symptoms certainly could be an MS thing. I've been known to use the wrong words, use words in the wrong order, slur, etc. Along the same lines, in the exacerbation that led to my diagnois, I would be typing along as I took notes of phone conversations and it was like I was in beginning typing again, going slow and repeatedly having to back up to redo letters and words.
It's frustrating, but somehow we muddle through it!