- Cues to voicing and aspiration of stops in onset position
- Voice onset time (VOT)
- Three phases of the stop release gesture in voiceless aspirated stops.
- The VOT continuum for implosive, fully voiced, voiceless unaspirated, voiceless aspirated and ejective stops
- Lisker and Abramson: Cross-language study of VOT (1964).
- VOT is insufficient for distinguishing 3-way types of stop contrasts in Korean or 4-way contrasts in Hindi.
- Korean stops: A three-way contrast of voicing, aspiration and tenseness
- Are the terms tense (fortis) and lax (lenis) appropriate for the voicing contrast in English obstruents?
- Voiceless - tense/fortis: stiff vocal folds, less compliant walls of vocal tract
- Voiced - lax/lenis: lax vocal folds, more compliant walls of vocal tract enabling
voicing to be sustained during oral closure phase.
- Cues to place of articulation in stop consonants
- Formant transitions for labial, alveolar and velar stops.
- A synthetic stop consonant continuum, based on formant transitions
- Release burst: level and locus (frequency range) of energy in labial, alveolar and velar stops.
- Stops in medial and coda position.
- In intervocalic (medial) position, voiced and voiceless stops may be distinguished by the relative duration and the presence/absence of vocal fold vibration during the closure phase.
- Voiced and voiceless alveolar stops tend to weaken to flaps or taps in medial position, particularly following a stressed vowel, e.g.: writer - rider, latter -ladder, etc. For illustrations of the stop - flap contrast in Warlpiri see: link
- In word final position, stops are frequently unreleased or glottalized in English and many other languages.
- Summarize the acoustic cues for stop consonants in different syllable positions.
5. Fricatives
- Are identified primarily by the quality of their frication noise, which is determined the aerodynamics of turbulent airflow at the point of constriction, the presence of any ‘down stream’ obstruction, and by the resonating characteristics of the vocal tract that ‘shape’ the spectrum of the noise source.
- Sibilant and non-sibilant fricatives: The role of the incisors - a ‘down stream’ obstruction for sibilant noise.
- Non-sibilants: [h], [ç], [k] as phonetic variants (allophones) of /h/ in Japanese. Note their articulatory differences, but the acoustic/auditory similarity of the noise sources.
- The voiced variants have similar noise energy distribution to their homorganic (same place) counterparts, though somewhat lower intensity, plus a low frequency (less than1kHz) component due to glottal energy source (voicing).
- The noise spectrum of [h] depends on the vocal tract shape for the following vowel. Compare hard and hid.
6. Nasals and nasalization
- Nasal consonants are like stops in that the oral airstream is completely blocked, but they are also resonant sounds (like approximants and vowels). They have both stop-like and resonant acoustic properties.
- Nasal segments have:
- Low frequency, voicing energy - a voice bar
- Very weak formant structure, made up of nasal resonances (nasal formants or ‘poles’) and anti-resonances (nasal anti-formants or ‘zeros’). The anti-resonances are regions of the spectrum robbed of acoustic energy, caused by the introduction of another resonator - the nasal cavity.
- Abrupt onset and offset, corresponding to the closure of the oral cavity (the stop gesture) and the direction of airstream through the nasal cavity. Release of the oral closure results in an equally abrupt offset registered on the spectrogram.
- Place of articulation in nasal consonants:
- Recognized from formant transitions on preceding or following vowels.
- See spectrogram ‘pin, Tim, king'
- Nasalization:
- Caused mainly by anticipatory lowering of velum prior to oral closure for the nasal consonant. Hence the familiar phonological rule: Vowels nasalize before an nasal consonant.
- Introduces nasal resonances and anti-resonances into the spectrogram, resulting in some ‘smearing’ of the vowel formant structure
- Nasal formants may be visible around 250, 2500, 3250 Hz.
- Because nasal resonances are fixed and tend to be different for different speakers, nasal murmur has been suggested as a useful acoustic signature for speaker identification.
7. Approximants
- The most vowel-like of consonants
- Composed almost entirely of formant transitions., which also serve to identify their respective places of articulation.
- The /r-l/ contrast:
- Not many languages have it.
- /r/ [‹] is characterized by a dramatic lowering of F3. There are two varieties of rhotic (‘r’ sound); one made by retracting the tongue tip (retroflexion), the other made by tongue bunching (tongue tip lowered with front of tongue bunched up to form a narrow central passage in the post-alveolar region). These two types of /r/ are acoustically indistinguishable on the spectrogram, and possibly on auditory grounds as well.
- The lateral approximant /l/ has a relatively abrupt onset and offset. Weak formant structure. No movement of F3.
- The /w-y/ contrast:
- These semi-vowels or glides have formant structure that resembles their respective vowels /i/ and /u/.
8. Spectrogram reading exercises (phonetic parlour games)
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