(Courtesy of XKCD.)
Sunday, August 2, 2009
Saturday, July 11, 2009
Tuesday, April 21, 2009
Tuesday, April 7, 2009
Anatomy Lesson #2
FORMANT FREQUENCIES
Formant frequencies are better explained in terms of resonances. The vocal folds are the primary modulators of frequency, and the sound produced would travel from the larynx through the pharynx and out the mouth or nose (in the case of nasal sounds, like the sound of [m]). However, the human ear perceives very subtle difference in sounds. Take English vowel sounds, for example:
[i] as in "heed"
[I] as in "hid"
There is only a subtle difference between the sounds [i] and [I], and yet any native English speaker will be able to produce them and tell them apart. Articulator structures (jaw, tongue, tongue, and velopharynx) allow us to manipulate frequences and to shape them into different sounds. Frequencies change when the shape of the cavity is changed, thus changing the resonance of the sound. This change of the voice envelope produces the distinct speech sounds, and each sound manifests with different characteristic peaks on a sound spectrum, as we can see on the graph below.
Each one of the peaks is known as a Formant frequency. Usually only 3 Formant frequencies are required to characterize a sound, and they are referred to as F1, F2, and F3. The first Formant frequency, F1, forms as the jaw is opening. F2 is influenced by the position of the back of the tongue, while F3 is influenced by the position of the tip of the tongue.
Clinical Relevance
Any deformity in the articulators, such as cleft palate or ankyloglossia (tongue-tie), will affect how the patient is able to shape his vocal cavity and therefore how some sounds are produced. Because of this, defective sounds should not be considered problems by themselves, but merely the manifestation of physical disease or certain structural peculiarities.
[Image credit: Georgia State University]
Formant frequencies are better explained in terms of resonances. The vocal folds are the primary modulators of frequency, and the sound produced would travel from the larynx through the pharynx and out the mouth or nose (in the case of nasal sounds, like the sound of [m]). However, the human ear perceives very subtle difference in sounds. Take English vowel sounds, for example:
[i] as in "heed"
[I] as in "hid"
There is only a subtle difference between the sounds [i] and [I], and yet any native English speaker will be able to produce them and tell them apart. Articulator structures (jaw, tongue, tongue, and velopharynx) allow us to manipulate frequences and to shape them into different sounds. Frequencies change when the shape of the cavity is changed, thus changing the resonance of the sound. This change of the voice envelope produces the distinct speech sounds, and each sound manifests with different characteristic peaks on a sound spectrum, as we can see on the graph below.
Each one of the peaks is known as a Formant frequency. Usually only 3 Formant frequencies are required to characterize a sound, and they are referred to as F1, F2, and F3. The first Formant frequency, F1, forms as the jaw is opening. F2 is influenced by the position of the back of the tongue, while F3 is influenced by the position of the tip of the tongue.Clinical Relevance
Any deformity in the articulators, such as cleft palate or ankyloglossia (tongue-tie), will affect how the patient is able to shape his vocal cavity and therefore how some sounds are produced. Because of this, defective sounds should not be considered problems by themselves, but merely the manifestation of physical disease or certain structural peculiarities.
[Image credit: Georgia State University]
Thursday, April 2, 2009
Notable Quote, #3
"What words say does not last. The words last. Because words are always the same, and what they say is never the same."
-Antonio Porchia, "Voces."
-Antonio Porchia, "Voces."
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