Fricatives

Question 1

What is the essential feature of a fricative?

Answer 1

a narrow constriction maintained somewhere in the vocal tract.

Question 2

What are examples of Fricatives in English?

Answer 2

Labiodental  (F, V)
Lingiodental (θ,ð)
Lingua alveolar (s,z)
Lingua Palatal (eg. ʃ)
Glottal (h)

Question 3

How are they produced?

Answer 3

fricatives are characterised by:

> > The formation of a narrow constriction somewhere in the vocal tract

> > The development of turbulent airflow

> > The generation of turbulence noise

Question 4

How do they compare to plosives and affricates???

Answer 4

fricatives have relatively long durations of noise. It is therefore the length of the interval of aperiodic noise that distinguishes fricatives as a sound class.

Question 5

What sources of energy to voiced fricatives have?

Answer 5

These (e.g /v/, /z/) are produced with two sources of energy:
Quasi-periodic energy of the vocal fold vibration
Aperiodic energy of the turbulence noise

Question 6

What sources of energy do voiceless fricatives have?

Answer 6

These (/f/, /s/) only have:

Aperiodic energy of the turbulence noise

Question 7

What are the spectral properties of friction noise?

Answer 7

Overall spectral shape of each fricative is mostly determined by the size and the shape of the oral cavity in the front of the constriction.

In general the longer the anterior cavity (front) the more defined the resulting spectrum. e.g alveolar and postalveolar fricatives have well defined distinct spectral shape. whilst Labiodental and interdental fricatives display and relatively flat spectrum.
Velar, uvular and pharyngeal fricatives have lower frequencies in the area of the first two formants.
Pharyngeal fricatives have a higher F1 than uvular fricatives.

Question 8

What are sibilants?

Answer 8

(s,z,ʃ,ʒ)

generally louder than non-sibilants and most of their energy is at higher frequencies (e.g as shown on spectrograms).
Sibilants are distinguished amongst each other in terms of noise spectrum and voicing.

Voiced sibilants spectrograms reveal that turbulent noise is pulsed by the voicing source, whilst in voiceless, continuous noise energy is evident in the waveform in the spectrum.

Question 9

What are the differences between Post-alveolar and alveolar sibilants?

Answer 9

Post-alveolar fricatives [ʃ,ʒ] typically exhibit a mid-frequency spectral peak around 2,500-3,500 Hz.
Alveolar [s, z] are produced with a shorter anterior cavity than [ʃʒ] and therefore display a primary spectral peak at higher frequencies, ranging from 4,000 to 7,000. Postalveolar have significant noise energy extending down to 3000 hz (for adult males.)

Question 10

What are the characteristics of non sibilants? examples

Answer 10

(f, v)

Weak in overall energy and have a flat diffuse spectra.Noise energy extends over a large frequency range

Question 11

What are the characteristics of labiodental and interdental fricatives?

Answer 11

[f, v] and [ɸð] are characterized by a relatively flat spectrum,
Research suggests - labiodentals may have a slightly higher spectral peak frequency (close to 8,000 Hz) than interdentals.

Question 12

What are the characteristics of velar fricatives?

Answer 12

Velar fricatives have a concentration of energy in the region of the F2 of the corresponding vowel.
Very little higher frequency energy

Question 13

What are the characteristic of Uvular and pharyngeal fricatives?

Answer 13

They differ in terms of the first formant
Pharyngeal fricatives have higher frequencies than uvular fricatives
Labiodental and interdental

Question 14

What are the amplitude differences between sibilants and non sibilants ?

Answer 14

Sibilant fricatives , possess intense noise energy. Sibilant compared to non sibilant fricatives have higher relative amplitude. e.g 10-15 db greater.

Question 15

Are voiced or voiceless fricatives longer in duration?

Answer 15

Shorter noise duration in voiced. (voicing important in distinguishing between voiced and voiceless)

Question 16

What are the formant transitions like in Fricatives?

Answer 16

The transitions in formants are longer in fricatives than in plosives, but not as long as glides. Research indicates that F2 at the onset of the vowel tends to increase as place of articulation moves further back in the oral cavity. Thee difference maybe due to the tongue forming a certain shape to produce the fricative turbulence.