The only thing consistent about stuttering is it's inconsistency. Literally, one of the hallmarks of stuttering is variability. Nothing is wrong with you. It comes with the territory of having a stutter. Stuttering is genetic. It isn't your fault. Anxiety doesn't cause stuttering but it does heighten it. Strong emotions can cause more repetitions/blocks. Any thought or feeling that triggers the fight, flight, freeze response will tighten muscles in the throat and mouth and quicken breathing which makes it physically harder to say words.