Chapter Three—Some physiological correlates
I. Aim of Physiological Discussions in this Monograph
Language, as any type of behavior, is seen as a manifestation of intricate physiological processes. In higher mammals the processes have many common denominators, but they have also undergone modifications in accordance with specializations in behavior.
（1）Respiratory adaptations in general
（2）Respiratory adaptations to language
（3）Other motor changes indirectly related to respiratory adaptations
Respiration, which is in many ways identical in a wide variety of species, shows particularly well forms of adaptations to species-specific behavior patterns.
III. Speech Production
（1）Discrete articulatory events
（2）Rate of articulatory events
（3）Ordering of articulatory events
IV. Problems Arising from Rate and Ordering
Throughout of duration of individual speech sounds, muscles must be activated at such rapid succession that a neuronal firing order must be assumed that functions with an accuracy of milliseconds.
V. The Problem of the Organizing Principle: Rhythm
（1）The rhythmic nature of articulation
（b）Signal switching between right and left ear
（c）Rate of interruptions
（d）Rate of syllable production
（f）Neurological correlates: EEG
（g）Neurological correlates: Pacing of speech during thalamic stimulation
Patterning in time is based on an underlying rhythmic metric. The hypothesis is advanced that the temporal patterns on which the neuromuscular automatisms are based have at their roots a physiological rhythm consisting of periodic changes of “states” at a rate of 6 + or – cps. Indirect evidence is cited that articulation itself reflects such a basic rhythm.
（2）Final comments on speech rhythmicity ( cultural, individual, and biological variations )