Speech production: Evidence for syntactically and phonologically determined units

The durational accuracy with which subjects can speak syntactically structured strings of words was compared with their accuracy in speaking word lists. These measurements underscored the great temporal precision of the human articulatory mechanism which appears to be the most precisely controlled movement system of the human body. Evidence is presented that when a syntactically structured message is being spoken, the centrally programmed innervational units involved in its articulatory implementation are greater in size and complexity than when a word list is being spoken.