Laterals + Nasals

December 2, 2009

Administrative Stuff• Friday: some notes on audition (hearing)

• Also: in-class USRIs

• Production Exercise #4 is due on Friday by 5 pm.

Laterals• Laterals are produced by constricting the sides of the tongue towards the center of the mouth.

• Ex: [l], a lateral approximant

• Laterals can also be formed by constricting on one side of the mouth only…

Lateral Palatography

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:

Breathy Voiced Nasals• Distinctions between voiced and breathy voiced nasals are also possible.

• Examples from Newari (spoken in Nepal):

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

[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 ]

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”

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?