Acoustic Phonetics Flashcards
(37 cards)
1
Q
What are phonemes?
A
- The smallest distinctive class of sounds in a language
- Defined linguistically, not acoustically
2
Q
What are allophones?
A
- Different sounds in one phoneme group
- Different pronunciations of the same underlying phoneme
3
Q
Compare the production of vowels vs consonants
A
- Vowels are always voiced with an open vocal tract, have complex periodic waveform
- Consonants can be voiced or voiceless, vocal tract is partially or fully obstructed, can have aperiodic waveform when voiceless
4
Q
What are some examples of phonetic features?
A
- Long vs short
- Nasality
- Sibilance (whistling quality)
5
Q
Compare monophthongs to diphthongs
A
- Monophthongs = short vowel sounds with constant tongue position
- Diphthongs = vowel sounds that change quality over one syllable
- Smooth movement of the tongue during vowel creates formant change
6
Q
Describe the properties of F1
A
- Related to the length of the pharyngeal cavity
- Inversely related to tongue height
- Higher F1 when tongue is lower
7
Q
Describe the properties of F2
A
- Related to the length of the oral cavity
- Depends on the front / back positioning of the tongue
- Front tongue = high F2, back tongue = low F2
8
Q
What are two articulatory effects on vowels?
A
- Partial constrictions in the vocal tract will affect resonances (e.g. formants lowered by constriction at the lips)
- Vowels are loud due to the open vocal tract (amplitude varies with mouth opening)
9
Q
What results in variability of formants?
A
- Inter-speaker: length of vocal tract, accent, dialect, social class, education, hearing loss
- Intra-speaker: context, emotion, health, word stress
10
Q
What are the three articulatory features of consonants?
A
- Voicing (whether there is vocal fold vibration)
- Manner (how articulators interact)
- Place (where constriction occurs along vocal tract)
11
Q
What are the voiced stops/plosives and their features?
A
- /b, g, d/
- Consonant is lower in amplitude than surrounding vowel
- Silence as air stream is stopped followed by noise burst when constriction released
- Periodic high amplitude vowel at end
- Low amplitude periodicity on spectrogram (voice bar)
12
Q
What are the voiceless stops/plosives and their features?
A
- /k, p, t/
- Longer period of silence
- No voice bar
- Noise burst followed by aspiration
- Voice onset time: delay from burst to start of vowel
13
Q
What are the features of all fricatives?
A
- Breath stream constricted but not stopped
- Turbulent airflow produces aperiodic noise
- Spectrum of noise depends on place of constriction and associated resonances
14
Q
What are the differences between voiced (zzz) and voiceless (sss) fricatives?
A
- Voiced: low amplitude but no silence, voice bar (low amplitude periodicity) visible
- fff, th(i), sss, shh, hhh
- Voiceless: aperiodic noise throughout (no silence), no voice bar during consonant
- vvv, th(e), zzz, shz
15
Q
What are the features of nasals?
A
- mm, nn, ng
- All voiced, periodic waveform
- Low amplitude, low frequency resonance (nasal murmur)
- Air is directed up through nasal cavity as velum is opened and breath stream through oral cavity is closed
16
Q
What are the features of affricates?
A
- ch-, dj-
- Combine the features of stops and fricatives
- Silent period > burst > frication noise
17
Q
What are the features of approximants?
A
- w-, y-, l-, r-
- Acoustically similar to vowels, with slightly reduced amplitude
- Periodic waveform with formant transitions
- F3 used to distinguish between /l/ and /r/
18
Q
Where do glottal constrictions occur?
A
Back of the throat, not obscured by tongue e.g. hhh
19
Q
Where do velar constrictions occur?
A
Tongue pressed against velum near back of the oral cavity e.g. /k/, /g/, /ng/
20
Q
Where do palatal and post-alveolar constrictions occur?
A
- Tongue pressed against palate at roof of oral cavity
- Palatal (y-) further back, post-alveolar (ch-, dj- sh-, sz-) more forward
21
Q
Where to alveolar constrictions occur?
A
Tongue pressed against roof of mouth, right behind teeth e.g /t/, /d/, /s/, /z/, /n/, /l/, /r/
22
Q
Where do linguodental constrictions occur?
A
Tongue between the teeth e.g. thh
23
Q
Where do labiodental constrictions occur?
A
Bottom lip between the teeth e.g. fff, vvv
24
Q
Where do bilabial constrictions occur?
A
Lips pressed together e.g. /p/, /b/, /m/, /w/
25
What are the two cues for place of articulation?
- Formant transitions and noise burst cues
- Difficult / impossible to see on waveform so spectral information is more important
26
What are formant transitions?
- Changes in the shape and resonances of the vocal tract as articulators move
- Transitions in F2 are important for differentiating voiced stops
27
What are the different locus of F2 points?
- Pointing towards a low frequency for /b/
- Pointing towards a mid frequency for /d/
- Pointing towards a high or mid frequency for /g/
28
What are noise burst cues?
- The frequency of bursts in relation to adjacent vowels, which helps to differentiate between voiceless stops
- High frequency burst = /t/
- Low frequency burst = /p/
- Burst close to vowel (mid frequency) = /k/
29
What are the voicing cues in stops?
Voiced:
- Voice bar visible for voiced stops
- Duration of preceding vowel is longer
Voiceless:
- Duration of noise burst is longer
- Voice onset time is longer
- Duration of closure of vocal tract is longer
30
What are three factors affecting everyday speech understanding?
- Distance (6dB drop in sound pressure per doubling of distance)
- Background noise
- Reverberation (increases with reflective surfaces and larger volume spaces)
31
How does speechreading complement hearing?
- At least 50% of speech perception is visual
- F1 represented by mouth opening or jaw movement
- F2 represented by mouth width or shape
- Difficult auditory cues easily seen, difficult visual cues easily heard
32
What are the acoustic cues at 125 & 250 Hz?
- F0
- Voicing cues
- Nasal murmur
- F1 for high vowels
33
What are the acoustic cues at 500 Hz?
- Primary manner cues
- F1 for most vowels
- Noise bursts for /p/ and /b/
- F1 transitions for semivowels
- Harmonics
34
What are the acoustic cues at 1000 Hz?
- Additional manner cues
- F1 & F2 transitions for some vowels and semivowels
- F2 transitions for vowels
- Noise bursts for plosives
- Harmonics
35
What are the acoustic cues at 2000 Hz?
- Primary place cues
- Additional manner cues
- F2 & transitions for for front vowels
- F3 for some vowels and semivowels
- Noise bursts for plosives & affricates
- Frication noises
- Harmonics
36
What are the acoustic cues at 4000 Hz?
- Secondary place cues
- F3 and transitions for most vowels
- Noise bursts for plosives and affricates
- Frication noises
- High harmonics
37
What are the acoustic cues at 8000 Hz?
Noise for all fricatives and affricates
