China
Africa
Explore chapters and articles related to this topic
Mechanisms and Models of Human Speech Production
Published in John Holmes, Wendy Holmes, Speech Synthesis and Recognition, 2002
For voiced sounds, which normally include all vowels and some consonants, such as [m, n, 1, w], the air flow from the lungs and up the trachea is modulated by vibrations of the vocal folds, located in the larynx. The vocal folds (sometimes also known as the vocal cords) are illustrated in Figure 2.2. They are two folds of tissue stretched across the opening in the larynx. The front ends of the folds are joined to the thyroid cartilage, and the rear ends to the arytenoid cartilages. The arytenoids can, under muscular control, move far apart so that there is a wide triangular opening between the vocal folds. This is the normal condition for breathing. They can also bring the folds tightly together, completely closing the top of the trachea. This condition is achieved when one holds one’s breath, and it occurs automatically during swallowing, to prevent food or drink from entering the lungs. The arytenoids can also be held so that the vocal folds are almost touching. If air is forced through the slit-like opening between them (known as the glottis), the folds will start to vibrate, and so modulate the air flow. The result is a build-up of vocal-fold oscillation whose frequency is mainly determined by the mass and tension of the folds, but is also affected by the air pressure from the lungs. The modulation of the air stream by the vibrating vocal folds is known as phonation. When the vibration amplitude has built up sufficiently, which usually happens after one or two cycles, the extent of the movement is such that the vocal folds make contact in the closing phase, thus completely and abruptly stopping the air flow.
Numerical analysis and comparison of flow fields in normal larynx and larynx with unilateral vocal fold paralysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Amirhossein Bagheri Sarvestani, Ebrahim Goshtasbi Rad, Kamyar Iravani
Phonation, as a key part of the voice production, is a sound generation process in the human larynx. This ability to couple phonation with articulation and resonance allows for human speech. The dynamics of the vocal folds and glottal jet are difficult to examine in experiments (Titze and Alipour 2006; Šidlof et al. 2008). Thus, much remains to be understood regarding the biophysics of phonation, despite a significant number of in-vitro and in-vivo studies (Švec and Schutte 1996; Titze and Martin 1998; Yang et al. 2010). A mathematical model that describes the dynamical process of phonation could complement experimental studies thereby paving the way for understanding the physics of voice production and helping the treatment of some of the most prevalent voice disorders.