Is there a term for someone who's thoughts mix lettering of words?

Sometimes when I'm thinking and writing/typing at the same time, the lettering of words in my thought don't match the ones I'm writing/typing.. like if I say "Server and shard." the thought will be "Sherver and sard." It sometimes comes out in my speech too. Is it a mental stutter or something? People keep telling me it's some kind of dyslexia, but from what I've learned about Dyslexia, I'd have trouble with fluency and comprehending things when I spell or read. As far as I've noticed, it's only a mental/verbal issue.