Laterals + Nasals

November 24, 2008

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.

Lateral Approximant Contrasts• Italian contrasts alveolar and palatal laterals.

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

[ ] [ ]

Dark vs. Clear /l/

[alala]

•/l/ often has low F2 in English because it is velarized.

Dark /l/ vs. /w/• Acoustically, velarized /l/ closely resembles /w/…

• or high, back, round vowels.

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.

Decreased Overall Amplitude

[m] [m]

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

Resonance in a closed tube

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 Comparison• A heavily damped wave wil die out more quickly...

• Than a lightly damped 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

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

breathy

[ ]

creaky

[ ]

Modal to Creaky

[ ]

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”