one viewpoint is, anxiety activates the **sympathetic nervous system** aka fight-or-flight response (more physiological arousal) this can disrupt muscle movements (legs, hands, speech movements etc) and impair executive functions like hyper-attention and over-monitoring. then it can cause non-stutterers to "trip" over their words. so it's essentially a form of *performance anxiety* at the speech level. i believe it's called situational disfluencies (vs [stuttering-like disfluencies](https://www.reddit.com/r/Stutter/comments/17s2qql/stuttering_vs_normal_disfluencies_whats_the/))