Grosjean F, Collins M
Phonetica. 1979;36(2):98-114. doi: 10.1159/000259950.
An analysis of the breathing patterns of speakers in a variable-rate reading task shows that the duration and frequency of breathing pauses are dependent both on the rate of speaking and the syntactic nature of the pause location. Non-breathing pauses follow the same pattern of occurrence as breathing pauses, but are always shorter and tend to occur primarily at minor constituent breaks. At slow and normal rates, speakers accommodate their need to inhale to the preplanned pause patterns. At fast rates, however, the physiological need to breathe is the sole determinant of pausing.
