Stop Acoustics and Glides

December 2, 2013

Where Do We Go From Here?• The Final Exam has been scheduled!

• Wednesday, December 18th

• 8-10 am (!)

• Kinesiology B 126

• Production Final:

• Just like the production exercises, except without the sound files to guide you!

• Due on December 18th, by 5 pm

• Will be e-mailed to you with the results of Production Exercise #4

• On Friday, we’ll have a brief review for the final exam.

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.

• American :

tongue tip between teeth

• British :

tongue tip behind upper teeth

• has a little bit of a transition cue

Transitions

[f] = ?

• In some dialects of English, may be replaced by [f].

• “with”

• “mouth”

• Stephen Fry transcription

• May be distinguished visually: check out the clips.

• Labio-dental and interdental fricatives are the most confusable consonants in English.

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

• [kw]: peak of labial protrusion occurs after stop closure

[k]

[w]

[k]

[w]

velum

lips

velum

lips

[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”