Transcript 25-Stops-Glides

Stop Acoustics + Glides
April 7, 2014
Down The Stretch They Come
• I have sent out your Production Exercise #2 grades!
• Production Exercise #3 comments will be sent out
tonight.
• Production Exercise #4 has been posted!
• Get your recordings in to me by Monday of next week.
• April 14th, 5 pm
• This Friday: Jacqueline will lead a review session +
spectrogram reading exercise.
• On Wednesday of this week: we’ll wrap up what we need
to do know about consonant acoustics.
• There will also be USRI evaluations.
Stop Acoustics Overview
•
Stages of Stop Production
1. Closing
2. Closure
3. Release
4. Opening
•
Acoustic Cues for Place of Articulation
1. Formant transition out of vowel
2. Closure voicing {or nothing}
3. Release burst
4. Formant transition into vowel
Release Bursts
• The acoustic characteristics of a stop release burst tend
to resemble those of a fricative made at the same place
of articulation.
• Ex: labial release bursts have a very diffuse spectrum,
just like bilabial and labio-dental fricatives.
[p] burst
Release Bursts: [t]
• Alveolar release bursts tend to lack acoustic energy at
the bottom of the spectrum.
• To some extent, higher frequency components are
more intense.
[t] burst
Release Bursts: [k]
• Velar release bursts are relatively intense.
• They also often have a strong concentration of energy
in the 1500-2000 Hz range (F2/F3).
• There can often be multiple [k] release bursts.
[k] burst
Closure Voicing
• During the stop closure phase, only low frequency
information escapes from the vocal tract (for voiced stops)
• “voicing bar” in spectrogram
• analogy: loud music from the next apartment
Armenian:
[bag]
• This acoustic information provides hardly any cues
to place of articulation.
[bag] vs. [bak]
• From Armenian (another language from the Caucasus)
[bag]
[bak]
Formant Transitions
• The resonant frequencies of the vocal tract change as
stop gestures enter or exit the closure phase.
• Ex: Formant frequencies usually decrease in making the
transition from bilabial stop to vowel (or vice versa)
Formant Transitions: alveolars
• For other places of articulation, the type of formant
transition that appears is more complex.
• From front vowels into alveolars, F2 tends to slope
downward.
• From back vowels into alveolars, F2 tends to slope
upwards.
[hid]
[hæd]
Formant Locus
• Whether in a front vowel or back vowel context...
• The formant transitions for alveolars tend to point to
the same frequency value. ( 1650-1700 Hz)
• This (apparent) frequency value is known as the locus of
the formant transition.
• According to one theory of perception...
• the locus frequency can be used by listeners to
reliably identify place of articulation.
Velar Transitions
• Velar formant transitions do not always have a reliable
locus frequency for F2.
• Velars exhibit a lot of coarticulation with neighboring
vowels.
• Fronter (more palatal) next to front vowels
• Locus is high: 1950-2000 Hz
• Backer (more velar) next to back vowels
• Locus is lower: < 1500 Hz
• F2 and F3 often come together in velar transitions
• “Velar Pinch”
The Velar Pinch
[bag]
[bak]
Fricative Transitions
• You get transition cues for fricatives at different places of
articulation, too.
Transitions
• American
:
tongue tip
between teeth
• British
:
tongue tip behind
upper teeth
•
has a little bit
of a transition cue
[f] =
?
• Labio-dental and interdental fricatives are the most
confusable consonants in English.
• In some dialects of English,
may be replaced by [f].
•
“with”
•
“mouth”
• Stephen Fry transcription
• May be distinguished visually: check out the clips.
Approximants
•
Approximants = one articulator is close to another, but
without producing audible turbulence.
•
They come in two flavors:
1. Glides (English [w], [j])
2. Liquids (English
, [l])
• This distinction is also phonological…
• Glides are essentially high-vowel articulations which
are not in a syllabic peak.
• In English, liquids may form syllables (or syllable
peaks).
Glides
• Each glide corresponds to a different high vowel.
Vowel
Glide
Place
[i]
[j]
palatal
(front, unrounded)
[u]
[w]
labio-velar
(back, rounded)
[y]
labial-palatal (front, rounded)
velar
(back, unrounded)
Glide Examples
• French contrasts palatal, labio-palatal and labio-velar
glides:
• Japanese has velar vowels, but not necessarily velar
glides...
Glide Acoustics
• Glides are shorter than vowels
• They also tend to lack “steady states”
• and exhibit rapid transitions into (or from) vowels
• hence: “glides”
• Also: lower in intensity
• especially in the higher formants
[j] vs. [i]
[w] vs. [u]
Vowel-Glide-Vowel
[iji]
[uwu]
More Glides
[wi:]
[ju:]
Secondary Articulations
• A secondary articulation is made by superimposing a
glide-like articulation on top of another constriction
elsewhere in the vocal tract.
• Note that secondary articulations are different from
double articulations.
• In double articulations, both constrictions are of equal
degree.
• Ex: labio-velar stops ([kp])
• With secondary articulations, there are two constrictions
with an unequal degree of closure.
• primary articulation: more constricted
• secondary articulation: less constricted
Primary / Secondary
• One example of a secondary articulation is velarized
• Also symbolized:
• Primary articulation: [l]
• direct contact with tongue tip
• Secondary articulation:
• approximation of velum with back of tongue
• The other commonly found secondary articulations are:
• [w]
labialization
• [j]
palatalization
•
pharyngealization
.
Labialization Examples
• In labialization, lip rounding (specifically, protrusion) is
superimposed on a fricative or stop constriction.
• Examples from Bura (spoken in Nigeria):
Timing
• The reason that [kw] is not transcribed as [kw] has to do
with timing.
• [kw]: peak of labial protrusion occurs during stop closure
velum
lips
[k]
[w]
• [kw]: peak of labial protrusion occurs after stop closure
velum
lips
[k]
[w]
[m] vs. [mw]
[mwanta]
Palatalization
• Consonants are palatalized by making a secondary [j]
constriction.
• Russian has contrastive palatalized consonants.
[p] vs. [pj] vs. [pj]
“sweat”
(male name)
“drink”
Post-vocalic Position
[toth]
• The acoustic effects of secondary articulations
operate in reverse, when they appear after a vowel.
Pharyngealization
• Consonants are pharyngealized by superimposing a
pharynx narrowing gesture on the regular consonant
articulation.
• Mid-sagittal diagrams from Arabic:
Arabic Examples
• Arabic contrasts pharyngealized and non-pharyngealized
consonants.
[t] vs.
[ti:n]
• Pharyngeal constrictions raise F1 and lower F2
• an
-like formant pattern