1. Articulation and Resonance
Articulation: Movement of structures along the vocal tract that change the resonance properties of the cavities in the V. tract
These movements change the physical properties (surface area, volume) of the different cavities
Changing the surface area/volume of different cavities produces different amounts or air at different locations
The air mass will help determine the frequency at which the air in the vocal tract vibrates

2. Articulation and Resonance
Cavities of the vocal tract: Pharynx
Consider the structure, shape, and the ways in which the pharyngeal shape and surface area can be changed
Wall of muscle forming posterior wall of vocal tract
Shape varied through the contraction of 3 main groups of muscles
level of larynx
level of hyoid
level of palate/mandible
The musculature changes the size of different portions of the pharynx, allowing energy at different freqs. to resonate

3. Articulation and Resonance
Cavities of the vocal tract: Pharynx
The pharyngeal cavity is often compared to a bottle filled with air – blowing across the top of the bottle sets the air in the bottle into motion
The air source in the pharynx, however, may be periodic as well as aperiodic
During phonation, the source is periodic, which will affect the pitch of the vocal tract output
Pharyngeal constrictors affect the amount of air in the pharynx by changing the cross sectional area at different locations

4. Articulation and Resonance
Generation of different sounds
Periodic - when phonated
Produces a harmonic complex in which harmonic frequencies are integer multiples of the F0
Aperiodic – for example whispering or frication in which the vocal folds slightly abducted so that they don’t vibrate, but allow a turbulent flow of air through
Flow of air blocked completely by some articulator (stop consonants, plosives)
Flow of air partially blocked and passed for a greater duration than when stopped (sibilants)
Combined sound sources
Refers primarily to voicing being produced concurrently with some form of constriction (stops, fricatives that are voiced)

5. Articulation and Resonance
Vowel production: Periodic sounds
Typically modeled by considering the vocal tract a series of coupled resonators
Vowel spectrum can be predicted from size and shape of the cavities
For vowels - Vocal tract considered a tube closed at one end
Powered by harmonic energy
The size of the average male vocal tract, for example, produces resonances at 500, 1500, and 2500 Hz when it is not constricted at any location (schwa)

6. Articulation and Resonance
Vocal tract resonances: Formants
Affected by physical characteristics discussed thus far that include cross-sectional area of cavities, vocal tract length, and F0
Named with regard to their frequency relative to other vocal tract resonances
For example, F1 is always lower in frequency than F2, which is always lower in frequency than F3, etc.
The source-filter theory provides predictions of formant frequencies based upon the nature and location of vocal tract constrictions

7. Articulation and Resonance
Source-Filter theory
The subglottal air pressure is the power source for speech
The vocal tract filters the power, or flow of air, by producing resonances related to the shape of the cavities through which the air flows
The talker has control over the shape of the cavities, therefore, the filtering action is intentional, and designed to produce sufficient contrast between speech sounds
Because resonances depend on the specific locations of constrictions, there is no longer a simple mathematical relationship between formant frequencies the way there is between harmonics and a fundamental

8. Articulation and Resonance
Source-Filter theory
The sub-glottal power source stimulates the air of the vocal tract at F0 and at harmonic frequencies
Harmonics are frequency components of complex sounds that are present at integer multiples of F0
Therefore 2nd Haromonic=2 x F0
3rd Harmonic=3 x F0, etc.
Harmonic frequencies and formant frequency are often different
The harmonics fill the sound spectrum, their overall level is shaped by the VT resonaces
In this way, energy filling a part of the spectrum at which a resonance occurs, it will be passed more efficiently than at other frequencies

9. Formants and Harmonics

10. Articulation and Resonance
Depictions of vocal output
Spectrograms – wide band and narrow band
Assess frequency, intensity, the amount of time
Distinguish harmonics from formants
The intensity of formants is obviously higher
Can also observe change in formant frequency as vowel identity is changed as in the production of a dipthong
The visible differences between formants is consistent with the articulatory, and auditory distinction

16. Articulation and Resonance
Vowel Production: The “point” vowels
/i/ - high, front, unrounded vowel - indicates the location of the tongue, which forms the constriction; and whether the lips are rounded or not
characterised by a high F2 & F3, and a low F1
Size of oral cavity dictates F2
Front vs. back constriction drives F3, in which front increases F3, back constriction lowers it
Therefore /i/ has a low F1, and a high F2 and F3

17. Articulation and Resonance
Vowel Production: The “point” vowels
/i/ - for the vowel /i/ the constrictions are placed according to what we know will be perceived as /i/
The constriction size can be measured using x-rays that take cross sectional slices of the vocal tract (OH)
For this vowel, the constriction is near the lips, at the end of the oral cavity, and the lower vocal tract is opened wide
Tongue is raised and fronted using the genioglossus muscle
Forms a small cavity in top “bottle” and a large cavity in the pharynx

18. Articulation and Resonance

19. Articulation and Resonance
Vowel Production: The “point” vowels
Again, formants are not necessarily centered at harmonic frequencies
But they reinforce certain frequency regions, and energy in these regions will be more intense at the opening of the mouth
We should then expect these formants to fall at different frequencies across different vowels
Some examples:

20. Articulation and Resonance
Vowel Production: The “point” vowels
/a/ low, back vowel
Must increase size of oral cavity by actively lowering jaw and/or lowering tongue
Jaw lowering with anterior belly of digastric
Tongue lowering with hyoglossus
Lowered jaw and tongue constrict oropharynx, producing larger oral cavity, smaller pharyngeal cavity
Note diff. formant freqs and their association to cavity sizes
Discernable using tactile sense (talker), & acoustic and visual senses (listener)
High F1, Low F2

21. Articulation and Resonance

22. Articulation and Resonance
Vowel Production: The “point” vowels
/u/ high, back vowel
Constriction at back of mouth, rather than front
Tongue raised by styloglossus (raises and backs toward styloid process)
Lips are protruded, lengthening v. tract, which lowers all formants
Posterior constriction pulls tongue back, enlarging oral cavity
Produces a low F1 and low F2.

23. Articulation and Resonance

24. x x x

25. Articulation and Resonance
Relation between tongue position and output spectra
Further forward tongue is placed
Higher F2
Further back
Lower F2, and a tendency to raise F1 Up
Lowers F1, and raises F2
Down
Raises F1, and lowers F2
However, position of the tongue is not as important as where the narrowest constriction is made (may be made in the pharynx regardless of the tongue’s position)

30. /i/
/u/

31. /i/
/u/

32. /Ɛ/
/I/

33. /Ɛ/
/I/

34. Articulation and Resonance
Consonant production
Resonant consonants
Semivowels, the glides /w/, /j/, and liquids /r/, /l/ have formant structures similar to vowels, but appear, in syllables, in the places that consonants appear (car, not crt)
The nasal consonants
Use of the velopharyngeal port modifies v. tract
/m/, /n/, /ng/

35. “REAL”

37. Articulation and Resonance
Consonant production
The nasal consonants
The velopharyngeal port is closed by backing the velum to the posterior pharyngeal wall - although different degrees of closure will be accomplished by raising the velum to different heights
Velopharyngeal port also responsible for adjusting the volume, and therefore the pressure, in the cavities above the larynx
Incorrect function can produce hypernasality, which is produced by too much air leaking into nasal cavity
Or hyponasality, which is produced by too little air passing through the nasal cavity

38. Articulation and Resonance
Consonant production
Nonresonant consonants - fricatives
Restricted flow of air, when compared to semivowels and nasals, therefore, no formant structure to speak of
Constriction causes turbulence and an aperiodic flow of air
The noise produced will resonate (just like blowing across the top of a bottle) effectively in the cavity immediately anterior to the turbulence
This is usually the front of the mouth, or the space between the lips and teeth

39. Articulation and Resonance
/life/
/aspire/

40. Articulation and Resonance
“MEAN”

41. Articulation and Resonance
Consonant production
Fricatives
labiodental (/f/, /v/) for which voicing produces the important distinction
linguadental (/th/, /the/) – again, voicing is the difference
Alveolar (/s/, /z/)
Palatal (/sh/, /zh/)
The stops - sounds produced when the V. tract is most thoroughly occluded (ptk, bdg)
moving from constriction in the front of the mouth to constriction at the rear changes the identity of the consonant from labial /p,b/ to velar /k,g/

42. /th aw/ /s aw/ /sh aw/ /ch aw/

43. Articulation and Resonance
“CHURCH”

44. Articulation and Resonance
“SAVE”

45. Articulation and Resonance
Consonant-Vowel combinations (CVs)
Rely upon rapid movements of articulators
Constrictions required for consonants
Open, or dilated cavities required for vowels
The rapid movements of articulators produce rapid changes in formant frequency, called formant transitions
These are considered important acoustic cues for speech perception
The further the articulators move, the greater the change in frequency resulting from the articulatory manipulation

46. Articulation and Resonance
/bab/, /dad/, /gag/

47. Articulation and Resonance
Voice-onset time
Amount of time needed for voiced air to reach the exit of the oral cavity is VOT
Longer as the constriction is moved further back
Voiceless stops have longer VOT than unvoiced
for /b/, voicing begins as the lips remain closed, and so upon release, the air flow is associated with voicing
for /p/ there is a preceding burst of air before the folds are adducted (peter vs. beater)

48. /b/
/p/