|Title:||Rhythmic Coordination in English Speech: An experimental study||Add Dissertation|
|Author:||Fred Cummins||Update Dissertation|
|Email:||click here to access email|
|Institution:||Indiana University Bloomington|
|Abstract:||Speech rhythm deals with the temporal coordination of events at a timescale which lies above the level of the segment, but below the level of whole phrases. It describes patterning among syllables and stress groups. This thesis starts by providing an algorithm for identifying a 'beat' as an event associated with the onset of a syllable-like unit. There follows a series of experiments designed to investigate the patterning of these beats, both by identifying constraints on their relative times of occurrence, and identifying conditions which influence their patterning.
The first series of experiments employs a task, referred to generically as 'speech cycling', in which subjects repeat a simple phrase along with an auditorily presented stimulus. They are asked to align specific syllables with repeating tones in the stimulus. Under these drastically constrained circumstances, subjects are found to show a very strong tendency to create an isochronous series of beats within one phrase repetition cycle. Different periodic divisions of the cycle correspond to a few discrete and stable production patterns. These stable patterns are consistent with an underlying oscillatory dynamic.
Continuous speech generates a train of beats. A method for identifying an underlying periodicity in such an event train is developed and tested both on simulated data and on beat trains derived from jazz recordings. Fluent prose readings are recorded at moderate and fast rates. Some of these, especially faster readings, exhibit a strong and measurable periodicity in the beat train. The underlying period identified seems to lie around 6~Hz.
Together, these findings strongly support the view that an isochronous series of beats, or a repeating temporal unit, emerges in response to coordinative demands on speech production. The repeating temporal unit serves as a framework with respect to which syllables or stressed syllables can be coordinated or phased.