Characteristic Time Intervals in Telephonic Conversation

HE time pattern of a conversation may be described in terms of the periods during which speech energy is issuing from the lips of each talker, the pauses with which each intersperses his speech, and the periods after the termination of a talker's speech during which the listener prepares to reply. On a telephone circuit this can be determined by the presence or absence of speech energy within the circuit, measured by an appropriate recording instrument. It is with observations of this type and the measurement of time intervals in conversation obtained in this manner with which the present paper is concerned. It will be well to keep in mind that the fundamental basis of these measurements is the presence or absence of speech energy. Many of the pauses recorded in this study are of the type which are known to occur within sentences, phrases, or even within words. Some of these are insufficient in duration to interrupt the continuity of the flow of speech, and some are too short to be noticed by a listener. The intervals as defined in this paper probably do not, therefore, exactly correspond to those which would be observed by a person listening to the conversations. The study and measurement of these intervals were originally undertaken to furnish information needed in the application of probability theory to the occurrence of lockouts on toll telephone circuits equipped with tandem voice-operated devices. This problem is treated in a companion paper by Mr. A. W. Horton, Jr.* Since that time, however, parts of the data have been used in various other technical applications, and it is therefore thought that the results of the study may have some general interest.