Stress reduction associated with slow, deep, regular, diaphragmatic-abdominal respiration has been attributed to arousal reduction and to diversionary effects on the cognitive mediation of stress. Evidence was presented to show that verbal inner speech, self-talk, is a primary cognitive mediator of stress and that inner speech is associated with speech musculature and irregular respiratory movements similar to those of external speech. It was proposed that, if with inner speech one uses and regulates speech musculature and irregular respiratory movements like external speech, then slow, deep, regular, diaphragmatic abdominal respiration may be incompatible with inner speech and may reduce stress by inhibiting stressful self-talk. In addition to describing a stress-reduction mechanism, a potential stress mechanism was suggested wherein fast, shallow, irregular, thoracic breathing and tension of speech musculature associated with stressful self-talk may promote the continuation of stressful self-talk.