Acoustic Phonetics

Question 1

Identify the acoustic features that distinguish among the different vowel types.

Answer 1

1) Central vowels are like an even closed-end tube –> F2 and F3 will be at odd multiples of F1 (evenly spaced)
2) Front vowels have more advanced tongue position –> F2 higher
3) Back vowels have less advanced tongue position –> F2 lower

Question 2

Identify the acoustic feature that distinguishes diphthongs from consonants.

Answer 2

Diphthongs have long formant transition durations due to changes in tongue and jaw positioning within the changing vowel qualities

Question 3

Identify the acousitc features that distinguish amongst approximants/ semi-vowels

Answer 3

1) Have relatively low F2 compared to vowels and other consonants
2) F3 (/l/ has higher F3 frequency than /r/ due to forward tongue position [i.e. shorter tube])

Question 4

Identify the major acoustic features that distinguish among stop consonants differing in place of articulation, in the syllable onset position

Answer 4

1) Frequency spectrum of stop release changes
- Anterior placement of tongue (bilabial and alveolar) = more diffuse (vv)
- /k/ has a compact burst spectrum with peak slightly above F2 (velar)
- /t/ has a high frequency, diffuse burst spectrum (alveolar)
- /p/ has a low frequency, diffuse burst spectrum (bilabial)

2) Starting frequency of F2
- Anterior placement of tongue = low start freq (vv)

Question 5

Identify the major acoustic features that distinguish among stop consonants differing in place of articulation, in the syllable final position

Answer 5

Direction of F2 transition (anterior placement = lower frequenct)

Question 6

Identify the major acoustic features that distinguish among stop consonants differing in voicing, in the syllable onset position

Answer 6

1) Presence/ absence of aspiration
- Voiced stops lack aspiration since vocal folds vibrate during closure phase, whilst voiceless stops exhibit aspiration due to burst of air after closure

2) Presence/ absence of voice bar
- Voiced stops have a voice bar (vv)

3) Voice onset time (VOT)
- Typically longer VOT for voiceless than voiced

Question 7

Identify the major acoustic features that distinguish among stop consonants differing in voicing, in the syllable final position

Answer 7

1) Duration of preceding vowel
- Voiceless stops have a shorted duration (vv)

2) Presence/ absence of voice bar
- same same

Question 8

Identify the major acoustic features that distinguish among fricative placement of articulation

Answer 8

posterior fricatives have clear spectral peaks, whilst anterior fricatives have flat and diffuse spectra

Question 9

Identify the major acoustic features that distinguish among voiced and voiceless fricatives

Answer 9

1) Presence/ absence of voice bar
2) Duration of preceding vowel
3) Intensity of noise spectrum (voiceless = more intense noise spectrum)

Question 10

Identify the major acoustic features that distinguish among nasals, regarding their place of articulation

Answer 10

High F2 for velar –> low F2 to bilabial

Question 11

Identify different ways in which acoustic phonetics can be applied in clinical practice

Answer 11

1) Assessment of clients
2) Treatment and tracking changes (i.e. improved articulation can be visually seen before being perceptually heard)
3) Biofeedback to modify output