UBC Wiki - User contributions [en]

Course:PHYS341/2018/project/mouth

2018-04-06T23:22:39Z

JoungChanKwon:

The '''mouth''' is a term for the organs found in the [https://en.wikipedia.org/wiki/Human_mouth#Structure vestibule] and [https://en.wikipedia.org/wiki/Human_mouth#Structure oral cavity proper], and is used in breathing, digestion, and communication.
==Acoustics of the mouth==

The production of speech is an outward force of air exhaled from the lungs, modulated by the [https://en.wikipedia.org/wiki/Glottis glottis] (vocal folds) and resonated by the mouth and its '''oral cavities''', one of the active components of the human voice. It is the means by which the sound input of the [https://en.wikipedia.org/wiki/Vocal_tract vocal tract] is modified before [https://en.wikipedia.org/wiki/Radiation radiating] into the environment. The vocal tract acts as the filter because the soft cavity walls suppress certain band of frequencies while intensifying others, allowing our ears to perceive the different vowels produced.

The production process occurs in two cavities, the mouth and the [https://en.wikipedia.org/wiki/Larynx larynx]. The two cavities work like a [https://en.wikipedia.org/wiki/Helmholtz_resonance Helmholtz resonator], where the two changing cavities interact with each other producing different vowels and consonants.

===Source-Filter model===
[[File:Voice production model signals.svg|left|alt=A drawing of the sound wave in three areas: the lungs, the larynx, and the oral cavity.|frame|The three stages of the sound wave in the source-filter model]]
The '''[http://newt.phys.unsw.edu.au/jw/voice.html#sfmodel Source-Filter model]''' defines the glottis as the source of [https://en.wikipedia.org/wiki/Harmonic harmonic] frequency, while the oral cavities and the vocal tract are the filter - hence, Source-Filter model. According to the Source-Filter model of speech production, the sound from the [https://en.wikipedia.org/wiki/Lung lungs] transforms twice before exiting through the mouth. The sound wave is modified once inside the larynx, and another time inside the vocal tract, which extends from the larynx at the opening of the glottis to the lips. Since the opening of the glottis is relatively small, the vocal tract is sometimes treated as a pipe - closed at the glottis and open at the lips. Between the larynx and the lips, sound passes through the [https://en.wikipedia.org/wiki/Pharynx pharynx] and the oral cavity, also known as the mouth. The first modification occurs in the larynx and is known as [https://en.wikipedia.org/wiki/Phonation phonation], and occurs in [https://en.wikipedia.org/wiki/Voice_(phonetics) voiced] (as opposed to https://en.wikipedia.org/wiki/Voice_(phonetics) non-voiced]) speech. The second modification occurs in the vocal tract, extending from the end of the larynx to the lips, and is known as [https://en.wikipedia.org/wiki/Articulation_(phonetics) articulation].

[[File:Illu01 head neck.jpg|thumb|right|Anatomy of the vocal tract]]

One should know that the source-filter model is only an approximation used to substitute for data that are either impractical or unethical to measure; the motions of the larynx and the motions of the vocal tract affect each other. For example, the sizes of the openings of the glottis are related to the [https://en.wikipedia.org/wiki/Resonance resonances] of the vocal tract. If the larynx is the first cavity while the mouth is the second cavity (similar to a Helmholtz Resonator), the relationship between vowels, [https://en.wikipedia.org/wiki/Formant formants], and cavities surfaces. When the first cavity is smaller than the second cavity, lower frequencies are emphasized over higher frequencies. Vice versa; when the first cavity is bigger than the second cavity, high frequencies are emphasized. The relationship between formant frequencies and vowels are further discussed below in the formant section of this article.

==Components of speech==
The study of the individual sounds of human speech is called [[Course:PHYS341/2018/project/mouth#Phonetics|phonetics,]] and an individual unit of speech is called a phone. Phonetics is a natural science based on the [https://en.wikipedia.org/wiki/Acoustics acoustic] and physical properties of sound, and is not dependent on the linguistic characteristics of any specified language. [[Course:PHYS341/2018/project/mouth#Phonology|Phonology]] is the study of [https://en.wikipedia.org/wiki/Phoneme phonemes]; a phoneme is the smallest distinctive unit of speech for a given language.

===Phonetics of speech===
[[File:Extended_IPA_chart_2005.png|thumb|alt=The systematic categorization of phonetic sounds using the International Phonetic Alphabet, created in 2005.|left|The 2005 version of the International Phonetic Alphabet chart.]]
Phonetically, speech is divided into two categories: vowels, which consist of uninterrupted airflow from the lungs, and consonants, sounds created when the airflow from the lungs is stopped by one of the mechanisms of the vocal tract. The [https://en.wikipedia.org/wiki/International_Phonetic_Alphabet International Phonetic Alphabet] categorizes vowels into the tongue's positions of height and its degree of backness (depth). Height is differentiated into three categories: high, middle, and low; depth has three categories: front, central, and back. The combination of height and depth positions of our tongue, and therefore the varying volume of oral cavities, produces the articulation of specific vowels.

Consonants can be divided into groups depending on whether they are voiced or unvoiced, where voiced consonants rely on the vibration of the vocal cords and different volumes of the oral cavities during the production of the sound and unvoiced consonants do not, instead relying on the movement and position of the lips and tongue. Consonants are also organized based on where the disruption of airflow is created inside the oral cavity.

[https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf Plosives] consist of complete disruptions of the airflow, such as the International Phonetic Alphabet consonants /p, t, k, b, d, g/. ''Nasal plosives'' are a kind of plosive where air continues to flow through the nose after being trapped in the oral cavity, such as the consonant /n/.

[https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf Fricatives] are a partial blockage of the airflow, causing friction through the creation of a narrow passage, such as using the lips to create the consonant /f/. Although the consonant /h/ is generated in the glottis and not the vocal tract, it is classified as a voiceless glottal fricative.

[https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf Affricatives] are a combination of the stop and the fricative, yet may be considered to be a single [[Course:PHYS341/2018/project/mouth#Phonemes|phoneme]] by a speaker of a language. An example is the j in judge.

[https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf Approximants] are partial blockages of air created by partial disruptions of the airway using the tongue, but to a lesser extent than the blockage seen in the fricative. Two examples are the phonemes /l/ in lap and /r/ in rap, which vary based on the path of air around the tongue.

===Phonology of speech===
[[File:Konkani_vowels_IPA_chart.gif|thumb|IPA Vowel Chart]]
A phoneme is the smallest unit of speech that distinguishes one word from another in a given language (for example, the initial consonants of cat and bat in English are phoneme.) The study of phonemes is called [https://en.wikipedia.org/wiki/Phonology phonology]. Sounds that are phonetically different may be considered to be the same phoneme by a speaker of a language; these similar sounds are grouped as a set of allophones of the related phoneme of that language: for example, in English, /d/ has two different allophones in the words ''dive'' and ''drive'', as the pronunciation of the d's is slightly different, yet both are considered to be the same phoneme, /d/.

The International Phonetic Alphabet categorizes vowels into the tongue's positions of height and its degree of backness (depth). Height is differentiated into three categories: high, middle, and low; depth has three categories: front, central, and back. The combination of height and depth positions of our tongue, and therefore the varying volume of oral cavities, produces the articulation of specific vowels. While each language has different vowels and pronunciations, the trapezoid is a standard shape for listing the vowels used in a given language.

===Perception of speech===
When producing speech, the resonant frequencies of our mouth cavities are called formants. If audio is transformed through a [https://en.wikipedia.org/wiki/Fast_Fourier_transform Fast Fourier Transformation] (FFT), the emphasized frequencies above the fundamental are called '''formants'''.

With vowels, the formant frequencies are what determines how produced speech is perceived. These formant frequencies vary based on one's language, dialect, and accent, and also one's perception. The values of the first and second formants (F1 and F2, respectively) are the most informative, allowing us to sufficiently distinguish the different vowels produced. The value of F3 is used as additional information for vowel identification, and the values of F4 and F5 affect the timbre, or the qualities of the voice. When analyzing sound, the formant F0 is found in voiced speech, but not in unvoiced speech. A special kind of formant, called the [http://www.savartjournal.org/index.php/sj/article/view/16/pdf singer's formant], is produced by merging formants F3 and F4, and occasionally F5, to produce a stronger and higher formant. It is termed the singer's formant as opera singers employ this technique to be heard over orchestras and choruses.

When frequencies are measured and analyzed through FFT analysis, we find that vowel phonemes and the first formant frequencies have an interesting relationship. Based on its height position, the vowels and the first formant frequencies have an inverse relationship. The produced vowel with low F1 frequencies are high vowels while high F1 frequencies are low vowels. Based on its degree of backness, vowels' backness and the second formant frequencies are directly related. Low F2 frequencies are produced by back vowels while high F2 frequencies are produced by front vowel.

Below we have a Fourier Transformation graph of the fundamental frequencies and the first and second formants of the vowels /a, i, e, o ,u/. The red curves indicate the range of emphasized formants with the red line to indicate the actual frequency of emphasis (F1, F2).

<gallery>
File:Vocal Formants (Ah).png|Fundamental; first formant (F1); second formant (F2) of the vowel /a/.
File:Vocal Formants (Ee).png|Fundamental; first formant (F1); second formant (F2) of the vowel /i/.
File:Vocal Formants (Eh).png|Fundamental; first formant (F1); second formant (F2) of the vowel /e/.
File:Vocal Formants (O).png|Fundamental; first formant (F1); second formant (F2) of the vowel /o/.
File:Vocal Formants (Oo).png|Fundamental; first formant (F1); second formant (F2) of the vowel /u/.
</gallery>

==References==
"Body Acoustics". https://www3.nd.edu/~nsl/Lectures/mphysics/Medical%20Physics/Part%20I.%20Physics%20of%20the%20Body/Chapter%204.%20Acoustics%20of%20the%20Body/Chapter%204.%20Acoustics%20of%20the%20Body.pdf Accessed 5 Mar. 2018

Coxhead, Peter. "Phones and Phonemes." https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf. Accessed 14 Mar. 2018.

Fleischer, Mario, et al. “Biomech Model Mechanobiol.” Formant Frequencies and Bandwidths of the Vocal Tract Transfer Function Are Affected by the Mechanical Impedance of the Vocal Tract Wall, doi:10.1007/s10237-014-0632-2.

Tai, Hwan-Ching, & Dai-Ting Chung. "Stradivari Violins Exhibit Formant Frequencies Resembling Vowels Produced by Females." Savart Journal. http://www.savartjournal.org/index.php/sj/article/view/16/pdf. Accessed 7 Mar. 2018

Wolfe, Joe et al. ''Voice Acoustics: an introduction''. Updated 2013. http://newt.phys.unsw.edu.au/jw/voice.html. Accessed 5 Mar. 2018

Course:PHYS341/2018/project/mouth

2018-04-06T20:53:48Z

JoungChanKwon:

The '''mouth''' is a term for the organs found in the [https://en.wikipedia.org/wiki/Human_mouth#Structure vestibule] and [https://en.wikipedia.org/wiki/Human_mouth#Structure oral cavity proper], and is used in breathing, digestion, and communication.
==Acoustics of the mouth==

The production of speech is an outward force of air exhaled from the lungs, modulated by the [https://en.wikipedia.org/wiki/Glottis glottis] (vocal folds) and resonated by the mouth and its '''oral cavities''', one of the active components of the human voice. It is the means by which the sound input of the [https://en.wikipedia.org/wiki/Vocal_tract vocal tract] is modified before [https://en.wikipedia.org/wiki/Radiation radiating] into the environment. The vocal tract acts as the filter because the soft cavity walls suppress certain band of frequencies while intensifying others, allowing our ears to perceive the different vowels produced.

The production process occurs in two cavities, the mouth and the [https://en.wikipedia.org/wiki/Larynx larynx]. The two cavities work like a [https://en.wikipedia.org/wiki/Helmholtz_resonance Helmholtz resonator], where the two changing cavities interact with each other producing different vowels and consonants.

===Source-Filter model===
[[File:Voice production model signals.svg|left|alt=A drawing of the sound wave in three areas: the lungs, the larynx, and the oral cavity.|frame|The three stages of the sound wave in the source-filter model]]
The '''[http://newt.phys.unsw.edu.au/jw/voice.html#sfmodel Source-Filter model]''' defines the glottis as the source of [https://en.wikipedia.org/wiki/Harmonic harmonic] frequency, while the oral cavities and the vocal tract are the filter - hence, Source-Filter model. According to the Source-Filter model of speech production, the sound from the [https://en.wikipedia.org/wiki/Lung lungs] transforms twice before exiting through the mouth. The sound wave is modified once inside the larynx, and another time inside the vocal tract, which extends from the larynx at the opening of the glottis to the lips. Since the opening of the glottis is relatively small, the vocal tract is sometimes treated as a pipe - closed at the glottis and open at the lips. Between the larynx and the lips, sound passes through the [https://en.wikipedia.org/wiki/Pharynx pharynx] and the oral cavity, also known as the mouth. The first modification occurs in the larynx and is known as [https://en.wikipedia.org/wiki/Phonation phonation], and occurs in [https://en.wikipedia.org/wiki/Voice_(phonetics) voiced] (as opposed to https://en.wikipedia.org/wiki/Voice_(phonetics) non-voiced]) speech. The second modification occurs in the vocal tract, extending from the end of the larynx to the lips, and is known as [https://en.wikipedia.org/wiki/Articulation_(phonetics) articulation].

[[File:Illu01 head neck.jpg|thumb|right|Anatomy of the vocal tract]]

One should know that the source-filter model is only an approximation used to substitute for data that are either impractical or unethical to measure; the motions of the larynx and the motions of the vocal tract affect each other. For example, the sizes of the openings of the glottis are related to the [https://en.wikipedia.org/wiki/Resonance resonances] of the vocal tract. If the larynx is the first cavity while the mouth is the second cavity (similar to a Helmholtz Resonator), the relationship between vowels, [https://en.wikipedia.org/wiki/Formant formants], and cavities surfaces. When the first cavity is smaller than the second cavity, lower frequencies are emphasized over higher frequencies. Vice versa; when the first cavity is bigger than the second cavity, high frequencies are emphasized. The relationship between formant frequencies and vowels are further discussed below in the formant section of this article.

==Components of speech==
The study of the individual sounds of human speech is called [[Course:PHYS341/2018/project/mouth#Phonetics|phonetics,]] and an individual unit of speech is called a phone. Phonetics is a natural science based on the [https://en.wikipedia.org/wiki/Acoustics acoustic] and physical properties of sound, and is not dependent on the linguistic characteristics of any specified language. [[Course:PHYS341/2018/project/mouth#Phonology|Phonology]] is the study of [https://en.wikipedia.org/wiki/Phoneme phonemes]; a phoneme is the smallest distinctive unit of speech for a given language.

===Phonetics of speech===
[[File:Extended_IPA_chart_2005.png|thumb|alt=The systematic categorization of phonetic sounds using the International Phonetic Alphabet, created in 2005.|left|The 2005 version of the International Phonetic Alphabet chart.]]
Phonetically, speech is divided into two categories: vowels, which consist of uninterrupted airflow from the lungs, and consonants, sounds created when the airflow from the lungs is stopped by one of the mechanisms of the vocal tract. The [https://en.wikipedia.org/wiki/International_Phonetic_Alphabet International Phonetic Alphabet] categorizes vowels into the tongue's positions of height and its degree of backness (depth). Height is differentiated into three categories: high, middle, and low; depth has three categories: front, central, and back. The combination of height and depth positions of our tongue, and therefore the varying volume of oral cavities, produces the articulation of specific vowels.

Consonants can be divided into groups depending on whether they are voiced or unvoiced, where voiced consonants rely on the vibration of the vocal cords and different volumes of the oral cavities during the production of the sound and unvoiced consonants do not, instead relying on the movement and position of the lips and tongue. Consonants are also organized based on where the disruption of airflow is created inside the oral cavity.

[https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf Plosives] consist of complete disruptions of the airflow, such as the International Phonetic Alphabet consonants /p, t, k, b, d, g/. ''Nasal plosives'' are a kind of plosive where air continues to flow through the nose after being trapped in the oral cavity, such as the consonant /n/.

[https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf Fricatives] are a partial blockage of the airflow, causing friction through the creation of a narrow passage, such as using the lips to create the consonant /f/. Although the consonant /h/ is generated in the glottis and not the vocal tract, it is classified as a voiceless glottal fricative.

[https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf Affricatives] are a combination of the stop and the fricative, yet may be considered to be a single [[Course:PHYS341/2018/project/mouth#Phonemes|phoneme]] by a speaker of a language. An example is the j in judge.

[https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf Approximants] are partial blockages of air created by partial disruptions of the airway using the tongue, but to a lesser extent than the blockage seen in the fricative. Two examples are the phonemes /l/ in lap and /r/ in rap, which vary based on the path of air around the tongue.

===Phonology of speech===
[[File:Konkani_vowels_IPA_chart.gif|thumb|IPA Vowel Chart]]
A phoneme is the smallest unit of speech that distinguishes one word from another in a given language (for example, the initial consonants of cat and bat in English are phoneme.) The study of phonemes is called [https://en.wikipedia.org/wiki/Phonology phonology]. Sounds that are phonetically different may be considered to be the same phoneme by a speaker of a language; these similar sounds are grouped as a set of allophones of the related phoneme of that language: for example, in English, /d/ has two different allophones in the words ''dive'' and ''drive'', as the pronunciation of the d's is slightly different, yet both are considered to be the same phoneme, /d/.

The International Phonetic Alphabet categorizes vowels into the tongue's positions of height and its degree of backness (depth). Height is differentiated into three categories: high, middle, and low; depth has three categories: front, central, and back. The combination of height and depth positions of our tongue, and therefore the varying volume of oral cavities, produces the articulation of specific vowels. While each language has different vowels and pronunciations, the trapezoid is a standard shape for listing the vowels used in a given language.

===Perception of speech===
When producing speech, the resonant frequencies of our mouth cavities are called formants. If audio is transformed through a [https://en.wikipedia.org/wiki/Fast_Fourier_transform Fast Fourier Transformation] (FFT), the emphasized frequencies above the fundamental are called '''formants'''.

With vowels, the formant frequencies are what determines how produced speech is perceived. These formant frequencies vary based on one's language, dialect, and accent, and also one's perception. The values of the first and second formants (F1 and F2, respectively) are the most informative, allowing us to sufficiently distinguish the different vowels produced. The value of F3 is used as additional information for vowel identification, and the values of F4 and F5 affect the timbre, or the qualities of the voice. When analyzing sound, the formant F0 is found in voiced speech, but not in unvoiced speech. A special kind of formant, called the [http://www.savartjournal.org/index.php/sj/article/view/16/pdf singer's formant], is produced by merging formants F3 and F4, and occasionally F5, to produce a stronger and higher formant. It is termed the singer's formant as opera singers employ this technique to be heard over orchestras and choruses.

When frequencies are measured and analyzed through FFT analysis, we find that vowel phonemes and the first formant frequencies have an interesting relationship. Based on its height position, the vowels and the first formant frequencies have an inverse relationship. The produced vowel with low F1 frequencies are high vowels while high F1 frequencies are low vowels. Based on its degree of backness, vowels' backness and the second formant frequencies are directly related. Low F2 frequencies are produced by back vowels while high F2 frequencies are produced by front vowel.

<gallery>
File:Vocal Formants (Ah).png|Fundamental; first formant (F1); second formant (F2) of the vowel /a/.
File:Vocal Formants (Ee).png|Fundamental; first formant (F1); second formant (F2) of the vowel /i/.
File:Vocal Formants (Eh).png|Fundamental; first formant (F1); second formant (F2) of the vowel /e/.
File:Vocal Formants (O).png|Fundamental; first formant (F1); second formant (F2) of the vowel /o/.
File:Vocal Formants (Oo).png|Fundamental; first formant (F1); second formant (F2) of the vowel /u/.
</gallery>

==References==
"Body Acoustics". https://www3.nd.edu/~nsl/Lectures/mphysics/Medical%20Physics/Part%20I.%20Physics%20of%20the%20Body/Chapter%204.%20Acoustics%20of%20the%20Body/Chapter%204.%20Acoustics%20of%20the%20Body.pdf Accessed 5 Mar. 2018

Coxhead, Peter. "Phones and Phonemes." https://www.cs.bham.ac.uk/~pxc/nlp/NLPA-Phon1.pdf. Accessed 14 Mar. 2018.

Fleischer, Mario, et al. “Biomech Model Mechanobiol.” Formant Frequencies and Bandwidths of the Vocal Tract Transfer Function Are Affected by the Mechanical Impedance of the Vocal Tract Wall, doi:10.1007/s10237-014-0632-2.

Tai, Hwan-Ching, & Dai-Ting Chung. "Stradivari Violins Exhibit Formant Frequencies Resembling Vowels Produced by Females." Savart Journal. http://www.savartjournal.org/index.php/sj/article/view/16/pdf. Accessed 7 Mar. 2018

Wolfe, Joe et al. ''Voice Acoustics: an introduction''. Updated 2013. http://newt.phys.unsw.edu.au/jw/voice.html. Accessed 5 Mar. 2018

File:Vocal Formants (O).png

2018-04-06T20:39:36Z