Although investigators have attempted to define the paralinguistic characteristics of spontaneous speech, there have been no systematic attempts to study its verbal reflections. An experiment comparing extemporaneous and impromptu speech samples of 10 freshman medical students showed that, of 10 verbal categories, only qualifying phrases significantly differentiated the two levels of spontaneity. A second study compared post-World War II presidential communications of different degrees of spontaneity. Speech samples were taken from inaugural addresses of seven presidents, and from both introductory remarks and responses to questions at their press conferences. The proportion of qualifying phrases significantly decreased as the amount of preparation increased, confirming the results of the student experiment. The use of qualifying phrases appears to represent, in part, an attempt by the speaker to avoid silence while retrieving and encoding memories from long-term storage.