laterals + nasals november 24, 2008 administrative stuff wednesday: quiz! then: voice onset time...
TRANSCRIPT
Administrative Stuff• Wednesday: quiz!
• Then: Voice Onset Time (VOT)
• Friday: Transcription Exercise
• On VOT contrasts in Thai and Bengali
• For next Wednesday: the final production exercise
• Fricatives, stops and VOT in:
• Thai, Quechua, Armenian, Ewe, Toda, Greek and Hebrew.
Where were we?• The IPA includes symbols for lateral approximants at four different places of articulation
Peter says:
• There are also two symbols for lateral fricatives.
• They are voiceless and voiced alveolars.
Retroflex Laterals• Toda contrasts dental and retroflex laterals.
• Toda is spoken in southern India.
• In syllable-final position, Korean laterals are typically retroflex.
Other Laterals• Mid-Waghi contrasts dental, alveolar and velar laterals.
• Mid-Waghi is spoken in the highlands of New Guinea.
• Zulu contrasts alveolar lateral approximants and fricatives.
• Zulu is spoken in South Africa.
Lateral Acoustics• Laterals have resonances like vowels…
Mid-Waghi: [alala]
• but are weaker in intensity.
[l] vs.• [l] and are primarily distinguished by F3
• much lower in
• Also: [l] usually has lower F2 in English
[ ] [ ]
Velarization in English• Different dialects:
1. [l] is velarized only in syllable-final position.
2. [l] is velarized everywhere except before front vowels.
3. [l] is velarized everywhere
Velarization in English
• Note: velarization of [l] leads to low F1 and low F2.
• closely resembles [o].
• Leading to dialect Option 4:
• The [l] disappears and the velarization is left behind.
• The Columbus, Ohio “[o:]dies” station
• Coldplay (Devon accent):
Nasals• Nasals are the sonorants with the greatest amount of constriction in the vocal tract.
• Nasals are produced with an open velo-pharyngeal port
• Flow of air is stopped in the mouth
• Air flows freely through the nose
• Air pressure does not build up behind stop constriction.
• Voicing is not impeded at the glottis.
• Note: the speech ready position
• Check out the Ken Stevens X-ray film.
Nasal Stops• Note: anywhere you can produce an oral stop, you can also produce a nasal stop.
• Check out all the nasals in Yanyuwa:
Plus One• You can also get a nasal stop at one place of articulation where oral stops never occur
• Labio-dental:
• Peter says: [ama]
• occurs allophonically in:
• English “dumbfounded”, “comfort”, (“Banff”)
• Catalan “infermer”; Italian “invece”
• Note: flow of air through nose reduces airflow through mouth
• vocal tract airflow too weak for frication at the labio-dental closure.
Voiceless Nasals• Nasalization is disastrous for fricatives.
• There are no (uncontroversial) nasal fricatives in the languages of the world.
• There are, however, voiceless nasals in a few languages.
• Examples from Burmese:
Nasal Acoustics• The acoustics of nasal stops are quite complex.
• Here’s the general pattern of what to look for in a spectrogram for nasals:
1. Periodic voicing.
2. Overall amplitude lower than in vowels.
3. Low frequency first formant.
4. Higher formants have low intensity.
5. Formants have broad “bandwidths”.
• Let’s account for each of these acoustic characteristics in turn.
Damping• The decreased overall amplitude of nasals is due to several factors, including damping.
• Recall that resonance occurs when:
• a sound wave travels through an object
• that sound wave is reflected...
• ...and reinforced, on a periodic basis
• The periodic reinforcement sets up alternating patterns of high and low air pressure
• = a standing wave
Damping, schematized• In a closed tube:
• With only one pressure pulse from the loudspeaker, the wave will eventually dampen and die out
• Why?
• The walls of the tube absorb some of the acoustic energy, with each reflection of the standing wave.
Damping Factors• The amount of damping in a tube is a function of:
• The volume of the tube
• The surface area of the tube
• The material of which the tube is made
• More volume, more surface area = more damping
• Think about the resonant characteristics of:
• a Home Depot
• a post-modern restaurant
• a movie theater
• an anechoic chamber
Inside Your Nose• In nasals, air flows through the nasal cavities.
• The resonating “filter” of nasal sounds therefore has:
• increased volume
• increased surface area
• increased damping• Damping decreases amplitude…
• And spreads energy across a wider range of frequencies.
• = increased bandwidth
Bandwidth in Spectrograms
The formants in nasals have increased bandwidth, in comparison to the formants in vowels.
F3 of [m] F3 of
Perceiving Nasal Place• Nasal “murmurs” do not provide particularly strong cues to place of articulation.
• Can you identify the following as [m], [n] or ?
• Repp (1986) found that listeners can only distinguish between [n] and [m] 72% of the time.
• Transitions provide important place cues for nasals.
• Repp (1986): 95% of nasals identified correctly when presented with the first 10 msec of the following vowel.
• Can you identify these nasal + transition combos?
[l] vs. [n]• Laterals are usually more intense than nasals
• less volume, less surface area = less damping
• break between vowels and laterals is less clear
[ ] [ n ]
Interlude: Voice Quality• I’ve talked about (at least) two different types of vocal
fold vibration:
1. modal
• vocal folds lightly adducted; flow of air causes periodic opening and closing of folds (“trilling”)
2. creaky
• vocal folds tensely adducted; low airflow causes irregular, low frequency voicing
3. breathy
• vocal folds slightly apart; flow of air makes folds “wave” in the wind
Voice Quality Movies
Source: http://www.ling.mq.edu.au/speech/physiology/movies/fibrescope/index.html
Contrasts• Gujarati contrasts breathy voiced vowels with modal voiced vowels:
• Jalapa Mazatec has a three-way contrast between modal, breathy and creaky voiced vowels:
Breathy Voiced Nasals• Distinctions between voiced and breathy voiced nasals are also possible.
• Examples from Newari (spoken in Nepal):
Nasal Plosion• One last, random thing about nasals--
• It is possible to “release” an oral stop closure by opening up the velo-pharyngeal port.
• The release burst caused thereby is referred to as nasal plosion.
• Peter says hidden, sadden, sudden, leaden
• with nasal plosion
• without nasal plosion
• Nasal plosion occurs in “pre-stopped” nasals in Russian:
• [dno] “bottom” [dna] “of the day”