Phonation

The term phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology and speech production in general. Phoneticians in other subfields, such as linguistic phonetics, call this process voicing, and use the term phonation to refer to any oscillatory state of any part of the larynx that modifies the airstream, of which voicing is just one example. Voiceless and supra-glottal phonations are included under this definition. The phonatory process, or voicing, occurs when air is expelled from the lungs through the glottis, creating a pressure drop across the larynx. When this drop becomes sufficiently large, the vocal folds start to oscillate. The minimum pressure drop required to achieve phonation is called the phonation threshold pressure (PTP), and for humans with normal vocal folds, it is approximately 2–3 cm H2O. The motion of the vocal folds during oscillation is mostly lateral, though there is also some superior component as well. However, there is almost no motion along the length of the vocal folds. The oscillation of the vocal folds serves to modulate the pressure and flow of the air through the larynx, and this modulated airflow is the main component of the sound of most voiced phones. The sound that the larynx produces is a harmonic series. In other words, it consists of a fundamental tone (called the fundamental frequency, the main acoustic cue for the percept pitch) accompanied by harmonic overtones, which are multiples of the fundamental frequency. According to the source–filter theory, the resulting sound excites the resonance chamber that is the vocal tract to produce the individual speech sounds. The vocal folds will not oscillate if they are not sufficiently close to one another, are not under sufficient tension or under too much tension, or if the pressure drop across the larynx is not sufficiently large.

Improving Children Speech Recognition through Feature Learning from Raw Speech Signal

Selen Hande Kabil, Subrahmanya Pavankumar Dubagunta

Children speech recognition based on short-term spectral features is a challenging task. One of the reasons is that children speech has high fundamental frequency that is comparable to formant frequency values. Furthermore, as children grow, their vocal ap ...

IEEE2019

Intrinsic viscoelasticity increases temperature in knee cartilage under physiological loading

Dominique Pioletti, Philippe Abdel Sayed, Mohamadreza Nassajian Moghadam

Metabolism of proteoglycans and hyaluronic acid has been shown to be temperature- dependent in cartilage explants, with optimal anabolic effects between 36 1C and 38 1C. At rest, the temperature of human knee has a value of around 33 1C. We aim to show in ...

Elsevier2014

Improving Children Speech Recognition through Feature Learning from Raw Speech Signal

Characterisation of voice quality of Parkinson's disease using differential phonological posterior features

Intrinsic viscoelasticity increases temperature in knee cartilage under physiological loading

Intrinsic viscoelasticity increases temperature in knee cartilage under physiological loading

Improving Children Speech Recognition through Feature Learning from Raw Speech Signal

Characterisation of voice quality of Parkinson's disease using differential phonological posterior features