Glottal pulse is a term used in the study of linguistics to describe the variances in voice quality affected by the manipulation of the folds of the vocal cords when speaking. In terms of mechanics, a glottal pulse is produced by a flap of tissue in the region of the vocal cords and the gap between them, which is jointly referred to as the glottis. Collectively, all of these areas form the vocal tract. The frequency produced in the glottal pulse results from the vibration of the vocal cords resonating against the larynx. This creates a buzz or hum that lends a distinctive quality to the voice of each individual.
Additional factors influence glottal pulse patterns. For instance, the rate of speed in which the glottis opens or closes bears an impact. When the vocal folds are pressed together, they form a glottal stop, which is necessary to produce the sound made when pronouncing the consonants “k” or “p.” However, a different glottal pulse is produced when air is forced through the passage and then filtered by the vocal cords, which occurs while pronouncing the letter “h.” In fact, each vocalization uttered results in a different sequencing of events that influence the passage and filtering of sound from the vocal tract.
Natural variations of glottal pulse are dependent on anatomical differences between individuals as well. For one thing, the overall size of the vocal cords makes a difference in the extent of filtering vocal productions and the resonance that results. The length of span between the mouth and the vocal cords is another structural factor that contributes to uniqueness in vocal quality.
Many linguists illustrate the acuity of glottal pulse by referring to it as the “acoustic coloring” of the voice. However, this line of thought is also used to extend beyond identifying individual distinctiveness to permit the formulation of general vocal qualities shared by voice types. Further, this model allows for derivatives in glottal pulse, while retaining the characteristics shared by similar voice types. In other words, even while co-factoring individual variations in pitch, reflection, and tone, similar vocal attributes may be extrapolated between speakers of the same sex, for instance. These corresponding characteristics are often referred to as glottal pulse shapes.
The practical usefulness behind determining glottal pulse primarily lies in gaining an understanding of how speech is processed. However, it also has an application in evaluating acoustics and detecting precise pitch. Global pulse tracking involves the use of sophisticated computer technology to achieve a digital analysis of raw speech samples. The data, which represents glottal pulse periods measured in kilohertz (kHz) frequencies, may then be plotted in a variety of algorithms to refine specific variations in speech.